Method of treating rheumatoid arthritis with an anti-IL-6R antibody

ABSTRACT

The present invention provides methods of preventing or treating rheumatoid arthritis using a fully human antibody or antigen-binding fragment thereof that specifically binds human interleukin-6 receptor (hIL-6R). The methods of the present invention may include administration of a second therapeutic agent, such as one or more of a non-steroidal anti-inflammatory drug (NSAID), a glucocorticoid, a disease-modifying anti-rheumatic drug (DMARD), or a TNF-alpha antagonist, T-cell blocker, anti-CD20 antibody, an IL-1, JAK or IL-17 antagonist, or any combination thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 13/286,261 filed Nov. 1, 2011, which is a divisional of U.S. patent application Ser. No. 12/780,006 filed on May 14, 2010, now U.S. Pat. No. 8,080,248, which is a continuation-in-part of U.S. patent application Ser. No. 12/501,657 filed on Jul. 13, 2009, now U.S. Pat. No. 8,043,617, which is a divisional of U.S. patent application Ser. No. 11/809,482 filed on Jun. 1, 2007, now U.S. Pat. No. 7,582,298, which claims the benefit under 35 U.S.C. §119(e) of U.S. provisional application Nos. 60/810,664 filed on Jun. 2, 2006; and 60/843,232 filed on Sep. 8, 2006. U.S. patent application Ser. No. 12/780,006 also claims the benefit under 35 U.S.C. §119(e) of U.S. provisional application Nos. 61/181,749 filed on May 28, 2009; 61/262,661 filed on Nov. 19, 2009; and 61/297,302 filed on Jan. 22, 2010. The disclosures of all the foregoing are herein incorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to the field of therapeutic treatment of rheumatoid arthritis. More specifically, the invention relates to the use of interleukin-6 receptor (IL-6R) antagonists, such as anti-IL-6R antibodies, to treat rheumatoid arthritis.

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of synovial tissue, leading to destruction of the joint architecture. It is recognized that cytokines such as tumor necrosis factor (TNF), interleukin-1 (IL-1) and interleukin-6 (IL-6) play a role in joint inflammation and cartilage damage observed in RA. IL-6 is a pleiotropic cytokine with biological effects on many cell types. IL-6 is often regarded as being downstream of TNF or IL-1 in inflammatory cytokine cascades and may therefore represent a common pathway factor in a wide range of inflammatory processes. Blockade of IL-6 signaling therefore offers the potential to ameliorate multiple pathogenic features of RA and other inflammatory diseases.

Therapeutic methods using IL-6R antagonists are mentioned in U.S. Pat. Nos. 5,888,510; 6,723,319; and 2001/0001663. Exemplary anti-IL-6R antibodies are described in U.S. Pat. Nos. 7,582,298; 6,410,691; 5,817,790; 5,795,695; 6,670,373; and 7,582,298.

BRIEF SUMMARY OF THE INVENTION

In a first aspect, the invention provides human antibodies, preferably recombinant human antibodies, that specifically bind human interleukin-6 receptor (hIL-6R). These antibodies are characterized by binding to hIL-6R with high affinity and slow dissociation kinetics and by the ability to neutralize IL-6 activity. The antibodies can be full-length (for example, an IgG1 or IgG4 antibody) or may comprise only an antigen-binding portion (for example, a Fab, F(ab′)₂ or scFv fragment), and may be modified to effect functionality, e.g., to eliminate residual effector functions (Reddy et al. (2000) J. Immunol. 164:1925-1933). In a preferred embodiment, the invention provides an antibody or antigen-binding fragment thereof, which binds human IL-6 receptor (SEQ ID NO:1) with a K_(D) of about 500 pM or less, as measured by surface plasmon resonance. In a more specific embodiment, the antibody or antigen-binding fragment has a K_(D) of less than 300 pM, or less than 200 pM, or even less than 100 pM. In various embodiments, the antibody or antigen-binding fragment thereof blocks hIL-6 activity with an IC₅₀ of 250 pM or less, as measured by luciferase bioassay. In more specific embodiments, the antibody or antigen-binding fragment thereof exhibits an IC₅₀ of 150 pM or less.

In related aspects, the antibody or antigen-binding fragment of the invention binds hIL-6R with an affinity at least 2-fold higher than it binds monkey IL-6R. In more preferred embodiments, the antibody or antigen-binding fragment binds hIL-6R protein (SEQ ID NO:1) with an affinity that is up to about 3-fold higher relative to its binding to monkey IL-6R (Macaca fascicularis extracellular domain shown in SEQ ID NO:251).

In one embodiment, the antibody or antigen-binding portion of the antibody of the invention comprises a heavy chain variable region (HCVR) selected from the group consisting of SEQ ID NO:3, 227, 19, 231, 35, 51, 67, 83, 99, 115, 131, 147, 239, 241, 163, 179, 235, 195 and 211, or substantially similar sequence thereof. In a more specific embodiment, the antibody or antigen-binding fragment thereof further comprises a light chain variable region (LCVR) selected from the group consisting of SEQ ID NO: 11, 229, 27, 233, 43, 59, 75, 91, 107, 123, 139, 155, 171, 187, 203 and 219, or a substantially similar sequence thereof. In specific embodiments, the antibody or antigen-binding fragment thereof comprise HCVR/LCVR pairs selected from the group consisting of SEQ ID NO:3/11; 227/229; 19/27; 231/233; 35/43; 51/59; 67/75; 83/91; 99/107; 115/123; 131/139; 147/155; 239/155; 241; 155; 163/171; 179/187; 235/237; 195/203; and 211/219, or substantially similar sequences thereof.

In a second aspect, the invention provides isolated nucleic acid molecules that encode an antibody or antigen-binding fragment of an antibody of the invention. In one embodiment, the nucleic acid molecule of the invention encodes an antibody or fragment thereof comprising an HCVR as described above. In specific embodiments, the nucleic acid molecule encoding the HCVR is selected from the group consisting of SEQ ID NO:2, 226, 18, 230, 34, 50, 66, 82, 98, 114, 130, 146, 238, 240, 162, 178, 234, 194 and 210, or a substantially identical sequence thereof. In a related aspect, the invention provides an isolated nucleic acid molecule encoding an LCVR as described above. In specific embodiments, the nucleic acid molecule encoding the LCVR is a nucleotide sequence selected from the group consisting of SEQ ID NO: 10, 228, 26, 232, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 236, 202 and 218, or a substantially identical sequence thereof.

In a third aspect, the invention features an antibody or antigen-binding fragment, comprising a heavy chain complementary determining region 3 (CDR3) domain and a light chain CDR3 domain, wherein: the heavy chain CDR3 domain comprises an amino acid sequence of the formula X¹—X²—X³—X⁴—X⁵X⁶—X⁷—X⁸—X⁹—X¹⁰—X¹¹—X¹²—X¹³—X¹⁴—X¹⁵—X¹⁶—X¹⁷—X¹⁸-X¹⁹ (SEQ ID NO:247) wherein X¹=Ala, X²=Lys, X³=Gly, X⁴=Arg, X⁵=Asp, X⁶=Ser or Ala, X⁷=Phe, X⁸=Asp; X⁹=Ile, X¹⁰=Pro or absent, X¹¹=Phe or absent, X¹²=Val or absent, X¹³=Tyr or absent, X¹⁴=Tyr or absent, X¹⁵=Tyr or absent, X¹⁶=Gly or absent, X¹⁷=Met or absent, X¹⁸=Asp or absent, and X¹⁹=Val or absent; and the light chain CDR3 domain comprises an amino acid sequence of the formula X¹—X²—X³—X⁴—X⁵—X⁶—X⁷—X⁸—X⁹ (SEQ ID NO:250) wherein X¹=Gln, X²=Gln or His, X³=Ala, X⁴=Asn or Tyr, X⁵=Ser, X⁶=Phe, X⁷=Pro, X⁸=Pro, and X⁹=Thr.

In a more specific embodiment, the antibody or antigen-binding fragment further comprises: a heavy chain CDR1 domain comprising an amino acid sequence of the formula X¹—X²—X³—X⁴—X⁵—X⁶—X⁷—X⁸ (SEC) ID NO:245) wherein X¹=Gly or Arg, X²=Phe, X³=Thr, X⁴=Phe, X⁵=Asp, X⁶=Asp, X⁷=Tyr, and X⁸=Ala; a heavy chain CDR2 domain comprising an amino acid sequence of the formula X¹—X²—X³—X⁴—X⁵—X⁶—X⁷—X⁸ (SEQ ID NO:246) wherein X¹=Ile or Val, X²=Ser, X³=Trp, X⁴=Asn, X⁵=Ser, X⁶=Gly, X⁷=Ser, and X⁸=Ile; light chain CDR1 domain comprising an amino acid sequence of the formula X¹—X²—X³—X⁴—X⁵—X⁶ (SEQ ID NO:248), wherein X¹=Gln, X²=Gly, X³=Ile, X⁴=Ser, X⁵=Ser, and X°=Trp; and a light chain CDR2 domain comprising an amino acid sequence of the formula X¹-X²-X³ (SEQ ID NO:249), wherein X¹=Gly or Ala, X²=Ala, and X³. Ser.

In a fourth aspect, the invention features an antibody or antigen-binding fragment, comprising: a heavy chain CDR3 domain selected from the group consisting of SEQ ID NO: 25, 153, 9, 185, 41, 57, 73, 89, 105, 121, 137, 169, 201 and 217; and a light chain CDR3 domain selected from the group consisting of SEQ ID NO:33, 161, 17, 193, 49, 65, 81, 97, 113, 129, 145, 177, 209 and 225.

In a more specific embodiment, the antibody or antigen-binding fragment further comprises: a heavy chain CDR1 domain selected from the group consisting of SEQ ID NO: 21, 149, 5, 181, 37, 53, 69, 85, 101, 117, 133, 165, 197, and 213; a heavy chain CDR2 domain selected from the group consisting of SEQ ID NO: 23, 151, 7, 183, 39, 55, 71, 87, 103, 119, 135, 167, 199 and 215; a light chain CDR1 domain selected from the group consisting of SEQ ID NO: 29, 157, 13, 189, 45, 61, 77, 93, 109, 125, 141, 173, 205 and 221; and a light chain CDR2 domain selected from the group consisting of SEQ ID NO: 31, 159, 15, 191, 47, 63, 79, 95, 111, 127, 143, 175, 207 and 223.

In specific embodiments, the antigen or antigen-binding fragment comprises heavy chain CDR sequences SEQ ID NO:21, 23, 25 and light chain CDR sequences SEQ ID NO:29, 31, 33; heavy chain CDR sequences SEQ ID NO:149, 151, 153 and light chain CDR sequences SEQ ID NO:157, 159, 161; heavy chain CDR sequences SEQ ID NO:5, 7, 9 and light chain SEQ ID NO: 13, 15, 17; and heavy chain CDR sequences SEQ ID NO: 181. 183, 185 and light chain CDR sequences SEQ ID NO:189, 191, 193.

In a fifth aspect, the invention features isolated nucleic acid molecules encoding an antibody or antigen-binding fragments of the invention, wherein the antibody or fragment thereof comprises: a heavy chain CDR3 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:24, 152, 8, 184, 40, 56, 72, 88, 104, 120, 136, 168, 200 and 216; and a light chain CDR3 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:32, 160, 16, 192, 48, 64, 80, 96, 112, 128, 144, 176, 208 and 224; as well as substantially identical nucleic acid sequences thereof.

In a more specific embodiment, isolated nucleic acid molecules are provided encoding an antibody or antigen-binding fragment of the invention, wherein the antibody or fragment thereof comprises: a heavy chain CDR1 encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:20, 148, 4, 180, 36, 52, 68, 84, 100, 116, 132, 164, 196 and 212; a heavy chain CDR2 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:22, 150, 6, 182, 38, 54, 70, 86, 102, 118, 134, 166, 198 and 214; a light chain CDR1 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:28, 156, 12, 188, 44, 60, 76, 92, 108, 124, 140, 172, 204 and 220; and a light chain CDR2 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO:30, 158, 14, 190, 46, 62, 78, 94, 110, 126, 142, 174, 206 and 222; as well as substantially identical nucleic acid sequences thereof.

The invention encompasses anti-hIL-6R antibodies or antigen-binding fragments thereof having a modified glycosylation pattern. In some applications, modification to remove undesirable glycosylation sites may be useful, or an antibody lacking a fucose moiety on an oligosaccharide chain, for example, to increase antibody-dependent cellular cytotoxicity (ADCC) (see Shield et al. (2002) JBC 277:26733). In other applications, modification of a galactosylation can be made in order to modify complement-dependent cytotoxicity (CDC).

In further aspects, the invention provides recombinant expression vectors carrying the nucleic acid molecules of the invention, and host cells into which such vectors have been introduced, as are methods of making the antibodies or antigen-binding fragments of the invention obtained by culturing the host cells of the invention. The host cell may be a prokaryotic or eukaryotic cell, preferably the host cell is an E. coli cell or a mammalian cell, such as a CHO cell.

In a further aspect, the invention features a pharmaceutical composition comprising a human antibody or antigen-binding fragment of an antibody which specifically binds hIL-6R and a pharmaceutically acceptable carrier.

The present invention additionally provides methods for treating rheumatoid arthritis. The methods of the present invention comprise administering to a patient in need of such treatment a therapeutically effective amount of a human antibody or antigen-binding fragment of an antibody which specifically binds to human interleukin-6 receptor (hIL-6R).

The studies summarized in Examples 8-12 below utilize an anti-hIL-6R antibody referred to as “mAb1.” This antibody is also referred to herein as VQ8F11-21. mAb1 (VQ8F11-21) comprises an HCVR/LCVR amino acid sequence pair having SEQ ID NOs:19127, and HCDR1-HCDR2-HCDR3/LCDR1-LCDR2-LCDR3 domains represented by SEQ ID NOs:21-23-251 SEQ ID NOs:29-31-33. However, the methods of the present invention can be practiced using any anti-IL-6R antibody disclosed herein, as well as variants and antigen-binding fragments of such antibody.

Examples 10-12 were designed to determine the effects of mAb1 administration on inflammation, as well as the safety and tolerability of mAb1 in RA patients, and to determine the time course of bioeffect on RA-associated markers after a subcutaneous dose of mAb1. As demonstrated in Example 12, dose-dependent reduction in high-sensitivity C-reactive protein (hsCRP) was observed through day 15 (p<0.0047). Suppression of serum amyloid A (SAA), erythrocyte sedimentation rate (ESR) and serum hepcidin was also observed in a dose-related manner. Significant increases in IL-6 were also observed. At day 8, a 200 mg dose of mAb1 was associated with median percent changes of −91.7% in hsCRP, -92.5% in SAA, -33.8% in ESR, -66.2% in hepcidin, and +647.0% in IL-6.

Safety data from all three studies (Examples 10-12) were combined [mAb1 (n=71) or placebo (n=24)]. During a maximum 16-week exposure period, 16.9% and 2.4% of patients receiving mAb1 and placebo had at least one neutrophil count of 1.0−1.5×10³/uL; and 7.0% and 0% had a neutrophil count of 0.5−1.0×10³/uL. During exposure, 50.1% and 20.1% of patients receiving mAb1 and placebo had at least one alanine aminotransferase (ALT) elevation 1-3 times the upper limit of normal (×ULN); 1.4% and 4.2% had ALT 3-5×ULN; and 1.4% and 0% had ALT >5×ULN. No alterations in neutrophils or liver enzymes were associated with adverse clinical outcomes.

In summary, IL-6R inhibition with subcutaneous administration of mAb1 was well tolerated in patients with RA with no dose-limiting toxicities observed. Target blockade was demonstrated by the significant increase in IL-6 after treatment. mAb1 administered to active RA patients resulted in dose-related reduction in hsCRP, SAA, and ESR; the observed reduction of hepcidin within one week of treatment is believed to be the first reported demonstration of hepcidin reduction in RA in humans. Moreover, hsCRP was suppressed for two weeks after a single 200 mg dose of mAb1, suggesting that weekly or bi-weekly SC dosing may prove to be efficacious.

The present invention also includes methods of modifying a rheumatoid arthritis-associated biomarker in a patient by administering to the patient an anti-hIL-6R antibody or antigen-binding fragment thereof. Exemplary RA-associated biomarkers include, e.g., high-sensitivity C-reactive protein (hsCRP), serum amyloid A (SAA), erythrocyte sedimentation rate (ESR), serum hepcidin, hemoglobin, and interleukin-6 (IL-6).

According to certain aspects of the present invention, the anti-hIL-6R antibody may be administered to a patient subcutaneously (s.c.) or intravenously (iv). The anti-hIL-6R antibody may also be administered to the patient in combination with one or more additional therapeutic agents. In certain embodiments, the anti-hIL-6R antibody is administered in multiple, sequential doses to a patient.

The present invention further includes the use of any of the anti-hIL-6R antibodies, antigen-binding fragments, and/or pharmaceutical formulations disclosed herein in the manufacture of a medicament for the treatment, prevention and/or amelioration of rheumatoid arthritis.

Other embodiments of the present invention will become apparent from a review of the ensuing detailed description.

DETAILED DESCRIPTION

Before the present invention is described, it is to be understood that this invention is not limited to particular methods and experimental conditions described, as such methods and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As used herein, the term “about,” when used in reference to a particular recited numerical value, means that the value may vary from the recited value by no more than 1%. For example, as used herein, the expression “about 100” includes 99 and 101 and all values in between (e.g., 99.1, 99.2, 99,3, 99.4, etc.).

Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to describe in their entirety.

Anti-hIL-6R Antibodies

The present invention includes methods that comprise administering to a patient a human antibody, or an antigen-binding fragment thereof, that binds specifically to hIL-6R. As used herein, the term “hIL-6R” means a human cytokine receptor that specifically binds human interleukin-6 (IL-6). In certain embodiments, the antibody that is administered to the patient binds specifically to the extracellular domain of hIL-6R. The extracellular domain of hIL-6R is shown in the amino acid sequence of SEQ ID NO:1.

Unless specifically indicated otherwise, the term “antibody,” as used herein, shall be understood to encompass antibody molecules comprising two immunoglobulin heavy chains and two immunoglobulin light chains (i.e., “full antibody molecules”) as well as antigen-binding fragments thereof. The terms “antigen-binding portion” of an antibody, “antigen-binding fragment” of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. Antigen-binding fragments of an antibody may be derived, e.g., from full antibody molecules using any suitable standard techniques such as proteolytic digestion or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and (optionally) constant domains. Such DNA is known and/or is readily available from, e.g., commercial sources, DNA libraries (including, e.g., phage-antibody libraries), or can be synthesized. The DNA may be sequenced and manipulated chemically or by using molecular biology techniques, for example, to arrange one or more variable and/or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add or delete amino acids, etc.

Non-limiting examples of antigen-binding fragments include: (i) Fab fragments; (ii) F(ab′)₂ fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; (vi) dAb fragments; and (vii) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region of an antibody (e.g., an isolated complementarity determining region (CDR)). Other engineered molecules, such as diabodies, triabodies, tetrabodies and minibodies, are also encompassed within the expression “antigen-binding fragment,” as used herein.

An antigen-binding fragment of an antibody will typically comprise at least one variable domain. The variable domain may be of any size or amino acid composition and will generally comprise at least one CDR which is adjacent to or in frame with one or more framework sequences. In antigen-binding fragments having a V_(H) domain associated with a V_(L) domain, the V_(H) and V_(L) domains may be situated relative to one another in any suitable arrangement. For example, the variable region may be dimeric and contain V_(H)-V_(H), V_(H)-V_(L) or V_(L)-V_(L) dimers. Alternatively, the antigen-binding fragment of an antibody may contain a monomeric V_(H) or V_(L) domain.

In certain embodiments, an antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting, exemplary configurations of variable and constant domains that may be found within an antigen-binding fragment of an antibody of the present invention include: (i) V_(H)-C_(H1); (ii) V_(H)-C_(H2); (iii) V_(H)-C_(H3); (iv) V_(H)-C_(H1)-C_(H2), (v) V_(H)-C_(H1)-C_(H2)-C_(H3), (vi) V_(H)-C_(H2)-C_(H3), (vii) V_(H)-C_(L); (viii) V_(L)-C_(H1); (ix) V_(L)-C_(H2), (x) V_(L)-C_(H3); (xi) V_(L)-C_(H1)-C_(H2), (xii) V_(L)C_(H1)-C_(H2)-C_(H3); (xiii) V_(L)-C_(H2)-C_(H3); and (xiv) V_(L)-C_(L). In any configuration of variable and constant domains, including any of the exemplary configurations listed above, the variable and constant domains may be either directly linked to one another or may be linked by a full or partial hinge or linker region. A hinge region may consist of at least 2 (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids which result in a flexible or semi-flexible linkage between adjacent variable and/or constant domains in a single polypeptide molecule. Moreover, an antigen-binding fragment of an antibody of the present invention may comprise a homo-dimer or hetero-dimer (or other multimer) of any of the variable and constant domain configurations listed above in non-covalent association with one another and/or with one or more monomeric V_(H) or V_(L) domain (e.g., by disulfide bond(s)).

The term “specifically binds,” means that an antibody or antigen-binding fragment thereof forms a complex with an antigen that is relatively stable under physiologic conditions. Specific binding can be characterized by a dissociation constant of at least about 1×10⁻⁶ M or smaller. Methods for determining whether two molecules specifically bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, and the like.

As with full antibody molecules, antigen-binding fragments may be monospecific or multispecific (e.g., bispecific). A multispecific antigen-binding fragment of an antibody will typically comprise at least two different variable domains, wherein each variable domain is capable of specifically binding to a separate antigen or to a different epitope on the same antigen. Any multispecific antibody format, including the exemplary bispecific antibody formats disclosed herein, may be adapted for use in the context of an antigen-binding fragment of an antibody of the present invention using routine techniques available in the art.

In specific embodiments, the antibody or antibody fragment for use in the method of the invention may be a multispecific antibody, which may be specific for different epitopes of one target polypeptide or may contain antigen-binding domains specific for epitopes of more than one target polypeptide. An exemplary bi-specific antibody format that can be used in the context of the present invention involves the use of a first immunoglobulin (Ig) C_(H3) domain and a second Ig C_(H3) domain, wherein the first and second Ig C_(H3) domains differ from one another by at least one amino acid, and wherein at least one amino acid difference reduces binding of the bispecific antibody to Protein A as compared to a bi-specific antibody lacking the amino acid difference. In one embodiment, the first Ig C_(H3) domain binds Protein A and the second Ig C_(H3) domain contains a mutation that reduces or abolishes Protein A binding such as an H95R modification (by IMGT axon numbering; H435R by EU numbering). The second C_(H3) may further comprise an Y96F modification (by IMGT; Y436F by EU). Further modifications that may be found within the second C_(H3) include: D16E, L18M, N44S, K52N, V57M, and V82I (by IMGT; D356E, L358M, N384S, K392N, V397M, and V422I by EU) in the case of IgG1 antibodies; N44S, K52N, and V82I (IMGT; N384S, K392N, and V422I by EU) in the case of IgG2 antibodies; and Q15R, N44S, K52N, V57M, R69K, E79Q, and V82I (by IMGT; Q355R, N384S, K392N, V397M, R409K, E419Q, and V422I by EU) in the case of IgG4 antibodies. Variations on the bi-specific antibody format described above are contemplated within the scope of the present invention.

A “neutralizing” or “blocking” antibody, as used herein, is intended to refer to an antibody whose binding to hIL-6R results in inhibition of the biological activity of hIL-6. This inhibition of the biological activity of hIL-6 can be assessed by measuring one or more indicators of hIL-6 biological activity known to the art, such as hIL-6-induced cellular activation and hIL-6 binding to hIL-6R (see examples below).

The fully-human anti-IL-6R antibodies disclosed herein may comprise one or more amino acid substitutions, insertions and/or deletions in the framework and/or CDR regions of the heavy and light chain variable domains as compared to, the corresponding germline sequences. Such mutations can be readily ascertained by comparing the amino acid sequences disclosed herein to germline sequences available from, for example, public antibody sequence databases. The present invention includes antibodies, and antigen-binding fragments thereof, which are derived from any of the amino acid sequences disclosed herein, wherein one or more amino acids within one or more framework and/or CDR regions are back-mutated to the corresponding germline residue(s) or to a conservative amino acid substitution (natural or non-natural) of the corresponding germline residue(s) (such sequence changes are referred to herein as “germline back-mutations”). A person of ordinary skill in the art, starting with the heavy and light chain variable region sequences disclosed herein, can easily produce numerous antibodies and antigen-binding fragments which comprise one or more individual germline back-mutations or combinations thereof. In certain embodiments, all of the framework and/or CDR residues within the V_(H) and/or V_(L) domains are mutated back to the germline sequence. In other embodiments, only certain residues are mutated back to the germline sequence, e.g., only the mutated residues found within the first 8 amino acids of FR1 or within the last 8 amino acids of FR4, or only the mutated residues found within CDR1, CDR2 or CDR3. Furthermore, the antibodies of the present invention may contain any combination of two or more germline back-mutations within the framework and/or CDR regions, i.e., wherein certain individual residues are mutated back to the germline sequence while certain other residues that differ from the germline sequence are maintained. Once obtained, antibodies and antigen-binding fragments that contain one or more germline back-mutations can be easily tested for one or more desired property such as, improved binding specificity, increased binding affinity, improved or enhanced antagonistic or agonistic biological properties (as the case may be), reduced immunogenicity, etc. Antibodies and antigen-binding fragments obtained in this general manner are encompassed within the present invention.

The term “epitope” refers to an antigenic determinant that interacts with a specific antigen binding site in the variable region of an antibody molecule known as a paratope. A single antigen may have more than one epitope. Epitopes may be either conformational or linear. A conformational epitope is produced by spatially juxtaposed amino acids from different segments of the linear polypeptide chain. A linear epitope is one produced by adjacent amino acid residues in a polypeptide chain. In certain circumstance, an epitope may include moieties of saccharides, phosphoryl groups, or sulfonyl groups on the antigen.

Therapeutic Administration and Formulations

The methods of the present invention comprise administering a therapeutically effective amount of an anti-hIL-6R antibody to a patient. As used herein, the phrase “therapeutically effective amount” means a dose of anti-hIL-6R antibody that results in a detectable improvement in one or more symptoms associated with rheumatoid arthritis or which causes a biological effect (e.g., a decrease in the level of a particular biomarker) that is correlated with the underlying pathologic mechanism(s) giving rise to the condition or symptom(s) of rheumatoid arthritis. For example, a dose of anti-hIL-6R antibody which causes an improvement in any of the following symptoms or conditions is deemed a “therapeutically effective amount”: chronic disease anemia, fever, depression, fatigue, rheumatoid nodules, vasculitis, neuropathy, scleritis, pericarditis, Felty's syndrome and/or joint destruction.

In accordance with the methods of the present invention, a therapeutically effective amount of anti-hIL-6R antibody that is administered to the patient will vary depending upon the age and the size (e.g., body weight or body surface area) of the patient as well as the route of administration and other factors well known to those of ordinary skill in the art. In certain embodiments, the dose of anti-hIL-6R antibody administered to the patient is from about 10 mg to about 500 mg. For example, the present invention includes methods wherein about 10 mg, about 15 mg, about 20 mg, about 25 mg, about 30 mg, about 35 mg, about 40 mg, about 45 mg, about 50 mg, about 55 mg, about 60 mg, about 65 mg, about 70 mg, about 75 mg, about 80 mg, about 85 mg, about 90 mg, about 95 mg, about 100 mg, about 105 mg, about 110 mg, about 115 mg, about 120 mg, about 125 mg, about 130 mg, about 135 mg, about 140 mg, about 145 mg, about 150 mg, about 155 mg, about 160 mg, about 165 mg, about 170 mg, about 175 mg, about 180 mg, about 185 mg, about 190 mg, about 195 mg, about 200, about 205 mg, about 210 mg, about 215 mg, about 220 mg, about 225 mg, about 230 mg, about 235 mg, about 240 mg, about 245 mg, about 250 mg, about 255 mg, about 260 mg, about 265 mg, about 270 mg, about 275 mg, about 280 mg, about 285 mg, about 290 mg, about 295 mg, about 300, about 325 mg, about 350 mg, about 375 mg, about 400 mg, about 425 mg, about 450 mg, about 475 mg, about 500 mg, or more of anti-hIL-6R antibody is administered to the patient.

The amount of anti-hIL-6R antibody that is administered to the patient may be expressed in terms of milligrams of antibody per kilogram of patient body weight (i.e., mg/kg). For example, the methods of the present invention include administering an anti-hIL-6R antibody to a patient at a daily dose of about 0.01 to about 100 mg/kg, about 0.1 to about 50 mg/kg, or about 1 to about 10 mg/kg of patient body weight.

The methods of the present invention include administering multiple doses of an anti-hIL-6R antibody to a patient over a specified time course. For example, the anti-hIL-6R antibody can be administered about 1 to 5 times per day, about 1 to 5 times per week, about 1 to 5 times per month or about 1 to 5 times per year. In certain embodiments, the methods of the invention include administering a first dose of anti-hIL-6R antibody to a patient at a first time point, followed by administering at least a second dose of anti-hIL-6R antibody to the patient at a second time point. The first and second doses, in certain embodiments, may contain the same amount of anti-hIL-6R antibody. For instance, the first and second doses may each contain about 10 mg to about 500 mg, about 20 mg to about 300 mg, about 50 mg to about 200 mg, or about 75 mg to about 150 mg of the antibody. The time between the first and second doses may be from about a few hours to several weeks. For example, the second time point (i.e., the time when the second dose is administered) can be from about 1 hour to about 7 weeks after the first time point (i.e., the time when the first dose is administered). According to certain exemplary embodiments of the present invention, the second time point can be about 1 hour, about 4 hours, about 6 hours, about 8 hours, about 10 hours, about 12 hours, about 24 hours, about 2 days, about 3 days, about 4 days, about 5 days, about 6 days, about 7 days, about 2 weeks, about 4 weeks, about 6 weeks, about 8 weeks, about 10 weeks, about 12 weeks, about 14 weeks or longer after the first time point. Third and subsequent doses may be similarly administered throughout the course of treatment of the patient.

The invention provides methods of using therapeutic compositions comprising anti-IL-6R antibodies or antigen-binding fragments thereof. The therapeutic compositions of the invention will be administered with suitable carriers, excipients, and other agents that are incorporated into formulations to provide improved transfer, delivery, tolerance, and the like. A multitude of appropriate formulations can be found in the formulary known to all pharmaceutical chemists: Remington's Pharmaceutical Sciences, Mack Publishing Company, Easton, Pa. These formulations include, for example, powders, pastes, ointments, jellies, waxes, oils, lipids, lipid (cationic or anionic) containing vesicles (such as LIPOFECTIN™), DNA conjugates, anhydrous absorption pastes, oil-in-water and water-in-oil emulsions, emulsions carbowax (polyethylene glycols of various molecular weights), semi-solid gels, and semi-solid mixtures containing carbowax. See also Powell et al. “Compendium of excipients for parenteral formulations” PDA (1998) J Pharm Sci Technol 52:238-311.

The dose may vary depending upon the age and the weight of a subject to be administered, target disease, conditions, route of administration, and the like. Various delivery systems are known and can be used to administer the pharmaceutical composition of the invention, e.g., encapsulation in liposomes, microparticles, microcapsules, receptor mediated endocytosis (see, e.g., Wu et al. (1987) J. Biol. Chem. 262:4429-4432). Methods of introduction include, but are not limited to, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, and oral routes. The composition may be administered by any convenient route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local.

The pharmaceutical composition can also be delivered in a vesicle, in particular a liposome (see Langer (1990) Science 249:1527-1533). In certain situations, the pharmaceutical composition can be delivered in a controlled release system, for example, with the use of a pump or polymeric materials. In another embodiment, a controlled release system can be placed in proximity of the composition's target, thus requiring only a fraction of the systemic dose.

The injectable preparations may include dosage forms for intravenous, subcutaneous, intracutaneous and intramuscular injections, local injection, drip infusions, etc. These injectable preparations may be prepared by methods publicly known. For example, the injectable preparations may be prepared, e.g., by dissolving, suspending or emulsifying the antibody or its salt described above in a sterile aqueous medium or an oily medium conventionally used for injections. As the aqueous medium for injections, there are, for example, physiological saline, an isotonic solution containing glucose and other auxiliary agents, etc., which may be used in combination with an appropriate solubilizing agent such as an alcohol (e.g., ethanol), a polyalcohol (e.g., propylene glycol, polyethylene glycol), a nonionic surfactant [e.g., polysorbate 80, HCO-50 (polyoxyethylene (50 mol) adduct of hydrogenated castor oil)], etc. As the oily medium, there are employed, e.g., sesame oil, soybean oil, etc., which may be used in combination with a solubilizing agent such as benzyl benzoate, benzyl alcohol, etc. The injection thus prepared is preferably filled in an appropriate ampoule.

Advantageously, the pharmaceutical compositions for oral or parenteral use described above are prepared into dosage forms in a unit dose suited to fit a dose of the active ingredients. Such dosage forms in a unit dose include, for example, tablets, pills, capsules, injections (ampoules), suppositories, etc. The amount of the antibody contained is generally about 1 to 500 mg per dosage form in a unit dose; especially in the form of injection, it is preferred that the antibody is contained in about 5 to 100 mg and in about 10 to 250 mg for the other dosage forms.

By the phrase “therapeutically effective amount” is meant an amount that produces the desired effect for which it is administered. The exact amount will depend on the purpose of the treatment, and will be ascertainable by one skilled in the art using known techniques (see, for example, Lloyd (1999) The Art, Science and Technology of Pharmaceutical Compounding).

In accordance with the methods of the present invention, the anti-hIL-6R antibody (or pharmaceutical formulation comprising the antibody) can be administered to the patient using any acceptable device or mechanism. For example, the administration can be accomplished using a syringe and needle or with a reusable pen and/or autoinjector delivery device. The methods of the present invention include the use of numerous reusable pen and/or autoinjector delivery devices to administer an anti-hIL-6R antibody (or pharmaceutical formulation comprising the antibody). Examples of such devices include, but are not limited to AUTOPEN™ (Owen Mumford, Inc., Woodstock, UK), DISETRONIC™ pen (Disetronic Medical Systems, Bergdorf, Switzerland), HUMALOG MIX 75/25™ pen, HUMALOG™ pen, HUMALIN 70/30™ pen (Eli Lilly and Co., Indianapolis, Ind.), NOVOPEN™ I, II and III (Novo Nordisk, Copenhagen, Denmark), NOVOPEN JUNIOR™ (Novo Nordisk, Copenhagen, Denmark), BD™ pen (Becton Dickinson, Franklin Lakes, N.J.), OPTIPEN™, OPTIPEN PRO™, OPTIPEN STARLET™, and OPTICLIK™ (sanofi-aventis, Frankfurt, Germany), to name only a few. Examples of disposable pen and/or autoinjector delivery devices having applications in subcutaneous delivery of a pharmaceutical composition of the present invention include, but are not limited to the SOLOSTART™ pen (sanofi-aventis), the FLEXPEN™ (Nova Nordisk), and the KWIKPEN™ (Eli Lilly), the SURECLICK™ Autoinjector (Amgen, Thousand Oaks, Calif.), the PENLET™ (Haselmeier, Stuttgart, Germany), the EPIPEN (Dey, L. P.), and the HUMIRA™ Pen (Abbott Labs, Abbott Park, Ill.), to name only a few.

The use of a microinfusor to deliver an anti-hIL-6R antibody (or pharmaceutical formulation comprising the antibody) to a patient is also contemplated herein. As used herein, the term “microinfusor” means a subcutaneous delivery device designed to slowly administer large volumes (e.g., up to about 2.5 mL or more) of a therapeutic formulation over a prolonged period of time (e.g., about 10, 15, 20, 25, 30 or more minutes). See, e.g., U.S. Pat. Nos. 6,629,949; 6,659,982; and Meehan et al., J. Controlled Release 46:107-116 (1996). Microinfusors are particularly useful for the delivery of large doses of therapeutic proteins contained within high concentration (e.g., about 100, 125, 150, 175, 200 or more mg/mL) and/or viscous solutions.

Combination Therapies

The present invention includes methods of treating rheumatoid arthritis which comprise administering to a patient in need of such treatment an anti-hIL-6R antibody in combination with at least one additional therapeutic agent. Examples of additional therapeutic agents which can be administered in combination with an anti-hIL-6R antibody in the practice of the methods of the present invention include, but are not limited to NSAIDs, DMARDs, TNFα antagonists, T-cell blockers, CD-20 antagonists (e.g., anti-CD-20 antibodies), IL-1 antagonists, JAK antagonists, IL-17 antagonists, and any other compound known to treat, prevent, or ameliorate rheumatoid arthritis in a human subject. Specific, non-limiting examples of additional therapeutic agents that may be administered in combination with an anti-hIL-6R antibody in the context of a method of the present invention include, but are not limited to methotrexate, sulfasalazine, hydroxychloroquine, leflunomide, etanercept, infliximab, adalimumab, golimumab, rilonacept, anakinra, abatacept, certolizumab and rituximab. In the present methods, the additional therapeutic agent(s) can be administered concurrently or sequentially with the anti-hIL-6R antibody. For example, for concurrent administration, a pharmaceutical formulation can be made which contains both an anti-hIL-6R antibody and at least one additional therapeutic agent. The amount of the additional therapeutic agent that is administered in combination with the anti-hIL-6R antibody in the practice of the methods of the present invention can be easily determined using routine methods known and readily available in the art.

Biomarkers

The present invention includes methods of treating rheumatoid arthritis by administering to a patient in need of such treatment a therapeutically effective amount of a human antibody or antibody binding fragment thereof which specifically binds to hIL-6R, wherein the level of one or more RA-associated biomarkers in the patient is modified (e.g., increased, decreased, etc., as the case may be) following administration. In a related aspect, the present invention includes methods for decreasing an RA-associated biomarker in a patient by administering to the patient a therapeutically-effective amount of a human antibody or antigen-binding fragment thereof which specifically binds to hIL-6R.

Examples of RA-associated biomarkers include, but are not limited to, e.g., high-sensitivity C-reactive protein (hsCRP), serum amyloid A (SAA), erythrocyte sedimentation rate (ESR), serum hepcidin, interleukin-6 (IL-6), and hemoglobin (Hb). As will be appreciated by a person of ordinary skill in the art, an increase or decrease in an RA-associated biomarker can be determined by comparing the level of the biomarker measured in the patient at a defined time point after administration of the anti-IL-6R antibody to the level of the biomarker measured in the patient prior to the administration (i.e., the “baseline measurement”). The defined time point at which the biomarker can be measured can be, e.g., at about 4 hours, 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 15 days, 20 days, 35 days, 40 days or more after administration of the anti-hIL-6R antibody.

According to certain embodiments of the present invention, a patient may exhibit a decrease in the level of one or more of hsCRP, SAA, ESR and/or hepcidin following administration of an anti-hIL-6R antibody to the patient. For example, at about day 8 following administration of a single dose of about 200 mg of an anti-hIL-6R antibody (e.g., mAb1), the patient may exhibit one or more of the following: (i) a decrease in hsCRP by about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more; (ii) a decrease in SAA by about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more; (iii) a decrease in ESR by about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or more; and/or (iv) a decrease in hepcidin by about 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or more.

According to certain other embodiments of the present invention, a patient may exhibit an increase in the level of one or more of Hb or IL-6 following administration of an anti-hIL-6R antibody to the patient. For example, at about day 8 following administration of a single dose of about 200 mg of an anti-hIL-6R antibody (e.g., mAb1), the patient may exhibit one or more of the following: (v) an increase in Hb by about 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0% or more; and/or (vi) an increase in IL-6 by about 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800% or more.

The present invention includes methods for determining whether a subject is a suitable patient for whom administration of an anti-hIL-6R antibody would be beneficial. For example, if an individual, prior to receiving an anti-hIL-6R antibody, exhibits a level of an RA-associated biomarker which signifies the disease state, the individual is therefore identified as a suitable patient for whom administration of an anti-hIL-6R antibody would be beneficial. According to certain exemplary embodiments, an individual may be identified as a good candidate for anti-hIL-6R therapy if the individual exhibits one or more of the following: (i) a level of hsCRP greater than about 4 mg/L (e.g., about 4.5 mg/L, about 5.0 mg/L, about 5.5 mg/L, about 6.0 mg/L, about 7.0 mg/L, about 10.0 mg/L, about 15.0 mg/L, about 20.0 mg/L, or more); (ii) a level of SAA greater than about 3800 ng/mL (e.g., about 4000 ng/mL, 4500 ng/mL, about 5000 ng/mL, about 5500 ng/mL, about 6000 ng/mL, about 10,000 ng/mL, about 20,000 ng/mL, about 25,000 ng/mL, about 30,000 ng/mL, about 35,000 ng/mL, about 40,000 ng/mL, about 45,000 ng/mL, or more); (iii) an ESR greater than about 15 mm/hr (e.g., about 16 mm/hr, about 17 mm/hr, about 18 mm/hr, about 19 mm/hr, about 20 mm/hr, about 21 mm/hr, about 22 mm/hr, about 25 mm/hr, about 30 mm/hr, about 35 mm/hr, about 40 mm/hr, about 45 mm/hr, about 50 mm/hr, or more); and/or (iv) a level of hepcidin greater than about 60 ng/mL (e.g., about 62 ng/mL, about 64 ng/mL, about 68 ng/mL, about 70 ng/mL, about 72 ng/mL, about 74 ng/mL, about 76 ng/mL, about 78 ng/mL, about 80 ng/mL, about 82 ng/mL, about 84 ng/mL, about 85 ng/mL, about 90 ng/mL, about 95 ng/mL, about 100 ng/mL, about 105 ng/mL, or more). Additional criteria, such as other clinical indicators of RA, may be used in combination with any of the foregoing RA-associated biomarkers to identify an individual as a suitable candidate for anti-hIL-6R therapy.

EXAMPLES

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the methods and compositions of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric.

Example 1 Generation of Human Antibodies to Human IL-6 Receptor

Immunization of rodents can be done by any methods known in the art (see, for example, Harlow and Lane (1988) supra; Malik and Lillehoj, Antibody techniques: Academic Press, 1994, CA). In a preferred embodiment, hIL-6R antigen is administered directly to mice which comprise DNA loci encoding both human Ig heavy chain variable region and Kappa light chain variable region (Veloclmmune™, Regeneron Pharmaceuticals, Inc.; U.S. Pat. No. 6,596,541), with an adjuvant to stimulate the immune response. Such an adjuvant includes complete and incomplete Freund's adjuvant, MPL+TDM adjuvant system (Sigma), or RIBI (muramyl dipeptides) (see O'Hagan, Vaccine Adjuvant, by Human Press, 2000, NJ). Such an adjuvant can prevent rapid dispersal of polypeptide by sequestering the antigen in a local depot, and may contain factors that can stimulate host immune response. In one embodiment, hIL-6R is administered indirectly as DNA plasmid that contains hIL-6R gene and expresses hIL-6R using the host cellular protein expression machinery to produce antigen polypeptide in vivo. In both approaches, the immunization schedule requires several administrations spaced by a few weeks. The antibody immune response is monitored by standard antigen-specific immunoassay. When animals reached their maximum immune response, the antibody expressing B cells were harvested and fused with mouse myeloma cells to preserve their viability, forming hybridoma cells. To select functionally desirable monoclonal antibodies, conditioned media of the hybridoma cells or transfected cells were screened for specificity, antigen-binding affinity, and potency in blocking hIL-6 binding to hIL-6R (described below).

Example 2 Anti-hIL6R Antibodies Generated Via Direct Isolation of Splenocytes

DNA encoding VH and VL domains may be isolated directly from a single antigen positive B cell. Briefly, the hIL-6Rα immunized transgenic mouse was terminated and splenocytes were harvested. Red blood cells were removed by lysis followed by pelleting the harvested splenocytes. Resuspended splenocytes were first incubated with a cocktail of human IgG, FITC-anti-mFc, and biotin-IL6Ra for 1 hour. The stained cells were washed twice with PBS, then stained with a cocktail of human and rat IgG, APC-anti-mIgM, and SA-PE for one hour. The stained cells were washed once with PBS and were analyzed by flow cytometry on a MoFlo (Cytomation). Each IgG positive, IgM negative, and antigen positive B cell was sorted and plated into a separate well on a 96-well plate. RT-PCR of antibody genes from these B cells was performed according to a method described by Wang et al. (2000) (J Immunol Methods 244:217-225). Briefly, cDNAs for each single B cell were synthesized via RT-PCR. Each resulting RT product was then split and transferred into two corresponding wells on two 96-well plates. One set of the resulting RT products was first amplified by PCR using a 5′ degenerate primer specific for human IgG heavy chain variable region leader sequence and a 3′ primer specific for mouse heavy chain constant region, to form an amplicon. The amplicon was then amplified again by PCR using a 5′ degenerate primer set specific for framework 1 of human IgG heavy chain variable region sequence and a nested 3′ primer specific for mouse heavy chain constant region. The other set of the resulting RT products was first amplified by PCR using a 5′ degenerate primer specific for human kappa light chain variable region leader sequence and a 3′ primer specific for mouse kappa light chain constant region to form an amplicon. The amplicon was then amplified again by PCR using a 5′ degenerate primer set specific for framework 1 of human kappa light chain variable region sequence and a nested 3′ primer specific for mouse kappa light chain constant region. The heavy chain and light chain PCR products were cloned into Sap I-linearized antibody vectors containing IgG1 heavy chain constant region and kappa light chain constant region, respectively. The heavy chain plasmid has a lox2272 site and a lox511 site flanking the heavy chain expression cassettes. In addition, immediately downstream of the lox2272 in the heavy chain plasmid there is a hygromycin-resistance gene that lacks a promoter and an initiating ATG. The hygromycin-resistance gene is also transcriptionally linked to a downstream eGFP gene via an IRES sequence. The light chain plasmid has a loxP site and lox2272 site flanking the light chain expression cassette. In addition, The light chain plasmid has a SV40 promoter immediately before an ATG at the lox2272 site, such that upon integration into an appropriate host cell the lox2272-proximal SV40 promoter and initiating ATG from the light chain plasmid is brought adjacent to the hygromycin-resistance gene in the heavy chain plasmid in the proper reading frame to allow transcription and translation of the hygromycin-resistance and eGFP genes. Purified recombinant plasmids having a heavy chain variable region sequence and plasmids having a light chain variable region sequence from the same B cell were then combined and transfected, together with a plasmid that expresses the Cre recombinase, into a modified CHO host cell line. The modified CHO host cell line contains, from 5′ to 3′, a loxP site, an eCFP, a lox2272 site, DsRed, and a lox511 site at a transcriptionally active locus. Consequently, the host CHO cell can be isolated by flow cytometry as a blue-positive, red-positive, and green-negative cell. When recombinant plasmids expressing heavy chain and light chain genes are transfected together with a plasmid expressing the Cre recombinase, site-specific recombination mediated by the Cre recombinase results in the integration of the antibody plasmids at the chromosomal locus containing the lox sites and replacement of the eCFP and DsRed genes. Recombinants can then be isolated as blue-negative, red-negative, and green-positive cells by flow cytometry. Accordingly, CHO cells transfected with recombinant plasmids having a heavy chain variable region sequence and plasmids having a light chain variable region sequence from the same B cell were sorted by flow cytometry, and proper recombinants that show the blue-negative, red-negative, and green-positive phenotype were isolated, and stable recombinant antibody-expressing CHO cell lines were established from isolated clones.

Example 3 Antigen Binding Affinity Determination

K_(D) of the antigen binding to the selected antibodies described above were determined by surface kinetics on a real-time biosensor surface plasmon resonance assay (BIAcore™). More specifically, the affinity of the antibodies for human IL-6R was measured using a BIAcore® 2000 or BIAcore® 3000. The antibody was captured on an anti-mouse IgG surface and exposed to various concentrations of recombinant hIL-6R protein either in monomeric or dimeric form. Kinetic analysis using BIAevaluation™ software was performed to obtain the association and dissociation rate constants.

Binding affinities of the antibodies to hIL-6R was also measured for either hybridoma-conditioned media or purified proteins by plate-based competition immunoassay. The antibody proteins were purified using Protein G affinity chromatography from hybridoma cell conditioning medium that was bovine IgG-depleted (Invitrogen). For the competition ELISA, briefly, constant amounts of antibody at different levels were premixed with serial dilutions of antigen protein, hIL-6R-hFc, ranging from 0 to 10 μg/ml, and incubated for two hours at room temperature to reach pseudo-binding equilibrium between the antibody and antigen. These solutions were then transferred to 96-well hIL-6R-hFc pre-coated plates to allow the free-antibody in the mixtures to bind to plate-coated hIL-6R-hFc. The plates were typically coated with 1 to 2 μg/ml hIL-6R-hFc protein in PBS solution overnight at 4° C. followed by BSA nonspecific blocking. After washing off excess antibody in solution, plate-bound antibodies were detected with an HRP-conjugated goat anti-mouse IgG or IgA polyclonal antibody reagent and developed using either colorimetric or chemiluminescence substrates. The dependency of the signals on the concentrations of antigen in solution was analyzed with a 4-parameter fit analysis using Prism™ software (Graph Pad) and reported as IC₅₀. Competition immunoassay were also carried out using steady state solution phase Kinexa™ instrument (Sapidyne Inc.).

Results are shown in Table 1 (control: humanized monoclonal antibody to human IL-6R (U.S. Pat. No. 5,817,790 SEQ ID NO:69 and 71). Antibody (HCVR and LCVR amino acid sequences): VQ8A9-6 (3, 11); VQ8F11-21 (19, 27); VV7G4-1 (35, 43); VV7G4-10 (51, 59) VV6C10-1 (67, 75); VV6C10-3 (83, 91); VV6C10-4 (99, 107); VV6F12-11 (115, 123); VV9A6-11 (131, 139); VV6A9-5 (147, 155), VV3D8-4 (163, 171); VV1G4-7 (179, 187); 248982-13-1-E5 (195, 203); 248982-13-2-A9 (211, 219). Monomer and dimer K_(D) determined by BIAcore™; solution K_(D) by Kinexa™; IC₅₀ by ELISA assays (n.d.=not determined).

TABLE 1 Antigen Binding Affinity K_(D) K_(D) Solution K_(D) ELISA IC₅₀ Monomer Dimer Monomer Dimer Antibody (nM) (nM) (nM) (nM) VQ8A9-6 0.222 0.101 0.120 0.004 VQ8F11-21 0.067 0.023 0.009 0.008 VV3D8-4 2.410 0.172 1.910 0.013 VV6A9-5 0.097 0.146 0.032 0.005 VV1G4-7 0.225 0.070 0.197 0.041 VV6C10-1 0.267 0.032 2.050 0.010 VV6F12-11 n.d n.d n.d 0.033 VV7G4-10 n.d. n.d. n.d. 1.980 VV9A6-11 n.d. n.d. n.d. 0.347 VV6C10-3 n.d. n.d. n.d. 0.009 248982-13-1-E5 0.987 0.785 n.d. 0.360 248982-13-2-A9 2.870 n.d. n.d. 0.054 Control 1.790 n.d. 1.960 n.d.

Example 4 Neutralization of hIL-6 Activity

hIL-6 blocking activities of the anti-hIL-6R antibodies of the invention were screened by hIL-6 blocking immunoassays, in vitro hIL-6 dependent cell growth bioassays, and surface plasmon resonance (BIAcore™). The immunoassay was used to screen ability of the tested antibody to block hIL-6 binding to hIL-6R, and the in vitro bioassay was used to determine the potency of the antibodies in neutralizing hIL-6R-mediated cellular signal transduction.

For the immunoassay, hIL-6 recombinant protein was coated on a 96-well plate in PBS buffer overnight at 4° C. This plate was used to capture free hIL-6R-hFc from antibody sample solutions, and the amount of captured hIL-6R-hFc was quantified according to the standard curve. The sample solutions were composed of a constant amount of hIL-6R-hFc recombinant protein (100 pM) and varying amounts of antibody, either in crude hybridoma condition medium or as purified antibody protein, ranging from 0 to about 50 nM in serial dilutions. The antibody-antigen mixtures were incubated at room temperature for ˜2 hours to allow antibody-antigen binding to reach equilibrium. The equilibrated sample solutions were then transferred to the hIL-6 coated plates for measurement of free hIL-6R-hFc. After 1 hour binding, the plate was washed and bound hIL-6R-hFc was detected using HRP-conjugated goat anti-hFc polyclonal antibodies (Jackson Immuno Research), and developed using TMB substrate (BD Pharmigen). IC₅₀s were determined as the amount of antibody required to reduce 50% of IL-6R-hFc detectable to plate bound hIL-6 ligand. Results are shown in the first column of Table 2.

Additionally, the ability of the test antibody to block hIL-6 binding to the hIL-6R receptor was determined using surface plasmon resonance. Purified antigen hIL-6R-hFc molecules were captured by goat anti-human IgG polyclonal antibodies immobilized on CM-5 surface through amine coupling to a density of 250 RU. hIL-6 solution (0.25 ml, 50 nM) was injected over the receptor surface and bound hIL-6 recorded (first injection of IL-6). Bound hIL-6 was then removed with a pulse of 3 M MgCl₂ following by conditioning buffer. Anti-hIL6R antibody in hybridoma conditioned medium was injected over the captured receptor surface followed by second injection of hIL-6. The percent reduction in hL-6 binding resulting from preformed antibody and receptor complex was used as a score to define hIL-6 blockers from non-blockers (second column, Table 2).

TABLE 2 Neutralization of hIL-6 Binding hIL6R/hIL6 hIL6/hIL6R XG-1 cell HepG2/Stat3 Binding Binding proliferation Luciferase Inhibition Inhibition Inhibition activity Antibody IC₅₀ (nM) (%) IC₅₀ (nM) IC₅₀ (nM) VQ8A9-6 0.39 68 0.40 0.097 VQ8F11-21 0.12 98 0.62 0.135 VV3D8-4 0.61 93 >100 n.d. VV6A9-5 0.35 100 1.10 0.188 VV1G4-7 1.10 34 1.80 0.578 VV6C10-1 4.60 61 >6.90 n.d. VV6F12-11 2.20 n.d. n.d. n.d. VV7G4-10 13.00 n.d. n.d. n.d. VV9A6-11 0.50 n.d. n.d. n.d. VV6C10-3 0.06 n.d. n.d. n.d. Control 2.20 91 1.50 0.854

The ability of hIL-6R antibodies to block hIL-6 activity in vitro was measured in the hIL-6-dependent myeloma line XG-1. XG-1 cells maintained in hIL-6-containing medium were washed twice with hIL-6-free media and cultured for ˜24 hours in hIL-6-free medium to deplete residual hIL-6. The starved cells were then spun down and re-suspended in the medium at 4×10⁵ cells per ml and plated 20,000 cells per well in a 96-well tissue culture plate. The purified antibody proteins were serially diluted in medium and added to the plated cells at concentrations ranging from 0 to 50 nM. Subsequently, recombinant hIL-6 was added to the wells to a final concentration of 8 pM. Cells were allowed to grow for ˜72 hours at 37° C. in a humidified 5% CO₂ incubator. At the end of growth period, live cells were measured using CCK-8 kit (Dojindo, Japan). IC₅₀s were determined as described above, and reported in the third column of Table 2.

The ability of hIL-6R antibodies to block hIL-6 activity was also measured in vitro in the hIL-6-responsive human hepatoma cell line, HepG2. HepG2 cells were transfected with a reporter plasmid containing a STATS (Signal Transducer and activator of Transcription 3) response element linked to a luciferase gene. The transfected cells were trypsinized, spun down and re-suspended in the medium at approximately 2.5×10⁵ cells per ml and plated at 20,000 cells per well in a 96-well tissue culture plate. The purified antibody proteins were serially diluted in medium and added to the plated cells at concentrations ranging from 0 to 100 nM. Subsequently, recombinant hIL-6 was added to the wells to a final concentration of 50 pM. The response was measured after incubating the cells for 6 hours at 37° C. in a humidified 5% CO₂ incubator. Luciferase activity was measured with the Steady-Glo™ luciferase assay system (Promega). IC₅₀s were determined as described above, and reported in the fourth column of Table 2.

Example 5 Binding Epitope Diversity

An antibody binding competition immunoassay was performed using as a control humanized antibody to human IL-6R. Briefly, a 96-well immunosorbent plate was coated with 20 ng per well hIL-6R recombinant protein overnight at 4° C. After blocking non-specific binding with BSA, the hIL-6R binding sites on one half of the plate were saturated with binding of the control antibody by addition of 500 ng of the control per well, and to the other half of the plate was added binding buffer only. After three hours binding at room temperature, the purified antibodies were spiked in at a final concentration of 50 ng/ml with and without the preexisting control antibody in the well. After one hour of additional binding, the free antibody was washed away and the plate-bound antibody was detected with HRP-conjugated goat anti-mouse IgG or IgA, polyclonal antibody and the plate was developed using chromatic HRP substrates and absorbance at 450 nm was recorded. Percentage deductions of the binding of the anti-hIL6R antibodies by the presence of the control antibody are listed in Table 3 below. A similar experiment was conducted using surface plasmon resonance technology (Table 3). Both methods generated consistent results. Antibodies VQ8F11, VV3D8, VV6A9, VV6C10-1 bound epitopes overlapping with the control antibody; while antibodies VQ8A9, VV1G4, VV6F12, VV7G4, VV9A6, and VV6C10-3 appeared to bind distinct epitopes as antigen binding was not blocked by the control antibody. Partial competition may result from steric hindrance from the first antibody bound, even though epitopes may not be overlapping.

TABLE 3 Competition of Antigen Binding with Control Antibody BIAcore ™ Immunoassay Antibody (% reduction) (% reduction) VQ8A9-6 26 3 VQ8F11-21 96 79 VV3D8-4 97 84 VV6A9-5 96 84 VV1G4-7 12 3 VV6C10-1 90 80 VV6F12-11 n.d. 3 VV7G4-10 n.d. 26 VV9A6-11 n.d. 18 VV6C10-3 n.d. 1

Example 6 Cross-Species Binding Property

Four antibodies were tested for cross-reactivity to monkey IL-6R recombinant protein using BIAcore™ technology. Briefly, a biosensor chip on which goat anti-mouse Fc polyclonal antibody was immobilized was used to present anti-hIL-6R monoclonal antibodies to a density of about 75 RU. Recombinant human or monkey monomeric IL-6R protein (Macaca fascicularis, extracellular domain; SEQ ID NO:251), at a concentration range between 1.25-40 nM, was injected over the antibody surface. The binding of the receptor to the antibody and the dissociation of the bound complex were monitored in real-time. Both association rate constant (ka) and dissociate rate constant (kd) were obtained, and K_(D) calculated (Table 4).

TABLE 4 Comparison of Binding Affinity to Human and Monkey IL-6R Antibody Antigen ka (M⁻¹S⁻¹) kd (S⁻¹) K_(D) (nM) Control Human IL6R 1.74E+05 1.67E−04 0.963 Monkey IL6R 1.44E+05 1.68E−04 1.170 VQ8F11-21 Human IL6R 8.51E+05 4.38E−05 0.051 (mAb1) monkey IL6R 3.39E+05 4.86E−05 0.143 VV1G4-7 Human IL6R 2.57E+05 6.18E−05 0.240 monkey IL6R no binding VV6A9-5 Human IL6R 5.18E+05 8.41E−05 0.162 monkey IL6R 5.00E+05 7.70E−05 0.154 VQ8A9-6 Human IL6R 7.32E+05 2.76E−04 0.377 monkey IL6R 7.31E+05 4.16E−04 0.569

Among the four tested antibodies, VQ8F11, VV6A9, and VQ8A9 strongly reacted to monkey receptor with K_(D) values that differed by about 1.5- to about 3-fold from human receptor binding, respectively. VV1G4, which was not blocked by the control antibody (Table 3), showed no binding to monkey receptor despite strong binding to the human receptor with K_(D) of 241 pM.

Example 7 Effect of Constant Region on Binding Affinity

The binding affinity to monomeric hIL-6R of four antibodies having mouse IgG, human IgG1 or human IgG4 (wild-type and modified) were determined using BIAcore™ as described above except a goat anti-human Fc polyclonal antibody surface was used to capture hIgG antibodies. Monomeric hIL-6R was injected at concentrations of 12.5, 6.25, 3.12, and 1.56 nM. The ability of the antibodies to neutralize hIL-6-dependent HepG2/STAT3 signal transduction was also determined in a luciferase assay (IC₅₀). IC₅₀s for different IgG isotypes were similar, suggesting no effect of isotype on antibody affinity for antigen.

TABLE 5 Comparison of IgG Isotypes Antibody IgG ka (M⁻¹S⁻¹) kd (S⁻¹) K_(D) (nM) IC₅₀ (nM) VQ8F11-21 hIgG1 6.22E+05 4.54E−05 0.073 0.150 (mAb1) hIgG4 7.17E+05 5.22E−05 0.073 0.228 mIgG2a 7.86E+05 5.27E−05 0.067 0.135 modhIgG4 8.81E+05 4.705−05 0.053 0.249 VQ8A9-6 hIgG1 1.09E+06 2.60E−04 0.238 0.130 hIgG4 1.17E+06 2.35E−04 0.201 0.185 mIgG1 9.95E+05 2.21E−04 0.222 0.097 VV6A9-5 hIgG1 7.12E+05 8.87E−05 0.125 0.204 hIgG4 5.67E+05 7.64E−05 0.135 0.343 mIgG2a 7.72E+05 7.52E−05 0.097 0.188 VQ1G4-21 hIgG1 3.34E+05 7.92E−05 0.237 0.767 hIgG4 2.73E+05 9.18E−05 0.336 0.528 mIgG2a 3.41E+05 7.66E−05 0.225 0.578

Example 8 Pharmacokinetics Studies of a Human Anti-IL-6R Antibody mAb1

The pharmacokinetics of mAb1 (HCVR SEQ ID NO:19 and LCVR SEQ ID NO:27) was examined in cynomolgus monkeys following a single subcutaneous (SC) or IV injection at multiple dose levels. Doses for SC administration were 1, 5, and 15 mg/kg; IV doses were 1 and 15 mg/kg. Blood samples were collected from all animals (N=6 per group, 3 per sex per group) at selected time points over a 52 day (1248 hr) time course. The resultant serum samples were analyzed using a validated ELISA assay for total mAb1 concentrations. The data were analyzed by means of noncompartmental methods. Pharmacokinetic (PK) parameter estimates such as observed maximal concentration in serum (Cmax), the time of observed maximal concentration (Tmax), area under the concentration vs. time curve (AUC), clearance (CL), volume of distribution (Vz), and mean residence time (MRT) were determined. The bioavailability following subcutaneous administration was approximately 78%.

At low doses, mAb1 had a half-life of 28 to 30 hr. At high doses, the terminal half-life estimate was approximately 225 hr when drug levels were above 10 μg/ml. The half-life was approximately 80 hr when serum concentrations were below 10 μg/ml.

Example 9 Toxicology Studies of Anti-IL-6R Antibody mAb1

In a GLP toxicology study, mAb1 was administered to cynomolgus monkeys via SC injection twice weekly for 13 consecutive weeks (total of 26 doses). Groups of 12 animals (6/sex) were administered 0 (placebo), 1, 5, 15 or 50 mg/kg/dose. Four animals/sex scheduled for the primary necropsy within 1 week of the end of dosing period and the remaining 2 animals/sex/group were assigned to a 12-week nondosing recovery period. The animals were observed for mortality and moribundity. Clinical examinations were performed daily and detailed physical examinations were performed weekly. Individual body weights were recorded weekly. Clinical pathology evaluations included hematology, serum chemistry, urine and CRP analysis. Blood samples were collected periodically for toxicokinetic and antibody evaluation. Ophthalmic and electrocardiogram examinations were performed periodically throughout the study. Complete necropsies were performed on all animals. Selected organs were weighed and selected tissues were examined microscopically. All animals survived to the scheduled primary or recovery necropsies. There were no test article-related clinical findings or effects on appetite, body weights, ophthalmologic examination results, electrocardiographic parameters, macroscopic findings or organ weights.

Results indicated that administration of mAb1 via subcutaneous injection to cynomolgus monkeys twice weekly for 13 consecutive weeks was well tolerated. Slight decreases in neutrophil counts, fibrinogen, and CRP values in monkeys administered mAb1 were considered to be effects or possible effects of test article administration, but were not considered to be adverse and in general, alterations in neutrophil counts and fibrinogen values resolved during the recovery period. CRP values were quite variable and alterations and subsequent resolution when compared to controls were not consistent in all groups. Test article treatment resulted in minimal to moderate perivascular mixed inflammatory cell infiltrates in dermis and/or subcutis in subcutaneous injection sites. Full or partial reversibility was evident following the recovery period. Findings of unclear relationship to test article treatment included severe diffuse subacute inflammation in heart in a single female administered 5 mg/kg and minimal focal subacute inflammation accompanied by mild perivascular mononuclear cell infiltrates in the brain of a single male administered 1 mg/kg. Toxicokinetic data indicate substantial systemic mAb1 exposure during the dosing phase of the study. In addition, 10 of the 16 recovery animals had circulating levels of mAb1 throughout the entire recovery period, while 6 animals had no detectable mAb1 at the end of the study. The no-observed-adverse-effect level (NOAEL) for subcutaneous injection of mAb1 to cynomolgus monkeys twice weekly for 13 consecutive weeks was 50 mg/kg.

Example 10 Single Dose Study in Subjects with Rheumatoid Arthritis

In order to evaluate the potential of mAb1 for treatment of RA, a study was conducted to evaluate safety, tolerability and pharmacokinetics of SC administered mAb1. The primary objective was to assess the safety and tolerability of a single dose of subcutaneously administered mAb1 in subjects with rheumatoid arthritis who were concomitantly treated with methotrexate. The secondary objective was to assess the PK profile of a single subcutaneous dose of mAb1 and immunogenicity of a single SC dose of mAb1

Endpoints. The primary efficacy endpoint was the percent change from Baseline in hs-C reactive protein (“hs-CRP”). Exploratory endpoints were the percent change in Subject's Assessment of Pain and Subject's Global Assessment of Disease activity.

Study Design. This is a multi-centered, randomized, double blind, placebo-controlled, single dose parallel group study of the safety, tolerability and pharmacodynamics of subcutaneously administered mAb1 in subjects with rheumatoid arthritis who were receiving concomitant methotrexate. Three (3) sequential cohorts of 5 subjects (4:1 active:placebo) were dosed SC with 50, 100, or 200 mg mAb1 or placebo. In each cohort, 1 week safety data from the first 2 subjects dosed was reviewed prior to dosing of the remaining subjects in the cohort. Screening took place within the window of 2 weeks to 3 days prior to the start of dosing (Day-14 to Day-3). On Study Day-1, the subjects underwent pre-dose study procedures and randomization. On Study Day 1, the subjects received SC blinded study drug or placebo. Subjects returned home following the 8 hour blood draw. Subjects returned to the clinic for outpatient visits on Study Days 3, 4, 8 (Week 1), 11, 15 (Week 2), 22 (Week 3), 29 (Week 4), 43 (Week 6), 57 (Week 8), 85 (Week 12) and 113 (Week 16), for safety assessments and blood sampling. Subjects completed an End of Study (EOS) visit on Study Day 113 (Week 16). Subjects who completed the study participated in 14 study visits.

Subject Eligibility. Inclusion Criteria: 1. Male or female ≧18 years of age; 2. Subjects must weigh >50 kg and <100 kg; 3. Diagnosis of Rheumatoid Arthritis (RA) as defined by the 1987 revised American College of Rheumatology (ACR) criteria with disease duration of no less than 6 months and ACR class I-III; 4. Subjects must receive a minimum of 8 weeks treatment with methotrexate (MIX) prior to the Screening visit. Subjects must be on a stable dose of MTX (7.5 to 25 mg/week) for a minimum of 4 weeks prior to the Screening Visit; 5. All subjects will take folic acid 1 mg daily or 5 mg weekly with the MTX dose, to minimize toxicity, according to local guidelines; 6. Oral prednisone ≦10 mg/day is allowed, as long as the dose is stable for 4 weeks prior to Screening and for the duration of the study; 7. For women of childbearing potential, a negative serum pregnancy test at the Screening Visit (Visit 1) and a negative urine pregnancy test at Day-1; 8. For men and women of childbearing potential, willingness to utilize adequate contraception and not become pregnant (or have their partner[s] become pregnant) during the full course of the study. Adequate contraceptive measures include oral contraceptives (stable use for 2 or more cycles prior to the Screening visit); IUD; DEPO-PROVERA®; NORPLANT® System implants; bilateral tubal ligation; vasectomy; condom or diaphragm plus either contraceptive sponge, foam or jelly.

Exclusion Criteria: 1. A history of Listeriosis or active tuberculosis (TB); 2. Persistent chronic or active recurring infection requiring treatment with antibiotics, antivirals, or antifungals within 4 weeks prior to the Screening Visit; 3. History of prior articular or prosthetic joint infection; 4. History of a hypersensitivity reaction, other than localized injection site reaction (ISR), to any biological molecule; 5. History of a hypersensitivity reaction to doxycycline, tetracycline or related compounds; 6. Significant concomitant illness such as, but not limited to cardiac, renal, neurological, endocrinological, metabolic or lymphatic disease that would adversely affect the subject's participation in this study; 7. Uncontrolled diabetes, defined as Hemoglobin A1c (HbA1c) ≧9.0% at the Screening Visit; 8. Presence of any of the following laboratory abnormalities at the Screening Visit: WBC <4,000/μl; platelet count <150,000/μl; neutrophils <2000/μl, AST/ALT >1.5×ULN; 9. Serum creatinine ≧1.5×ULN at the Screening Visit; 10. Subjects with a positive intradermal skin tuberculin test (PPD 5TU)≧5 mm induration read at 48 to 72 hours after placement; 11. Chest radiograph (at the Screening visit) consistent with prior tuberculosis infection including, but not limited to, apical scarring, apical fibrosis, or multiple calcified granulomata. This does not include non-caseating granulomata; 12. Use of parenteral or intra-articular glucocorticoids within 4 weeks prior to the Screening Visit; 13. Treatment with anakinra within two weeks prior to the Screening Visit; 14. Treatment with etanercept, cyclosporine, mycophenolate, tacrolimus, gold, penicillamine, sulfasalazine, or hydroxychloroquine within 4 weeks prior to the Screening Visit; 15. Treatment with adalimumab within 6 weeks prior to the Screening Visit; 16. Treatment with abatacept, azathioprine, cyclophosphamide or infliximab within 12 weeks prior to the Screening Visit; 17. Treatment with leflunomide or rituximab within 6 months prior to the Screening Visit; 18. Treatment with tocilizumab or any anti-IL-6 medications prior to Screening Visit; 19. Received administration of any live (attenuated) vaccine within 3 months prior to the Screening Visit; 20. Known history of Human Immunodeficiency Virus (HIV) antibody; and/or positive Hepatitis B surface antigen (HBsAg), and/or positive Hepatitis C antibody (HCV) at the Screening Visit; 21. History of malignancy other than carcinoma in-situ of the cervix, or adequately treated, non-metastatic squamous or basal cell carcinoma of the skin within five years prior to Screening Visit; 22, History of demyelinating disease or multiple sclerosis; 23. History of myeloproliferative disorder; 24. History of alcohol or drug abuse within the 5 years prior to the Screening Visit; 25. Any subject who has had surgery within 4 weeks prior to the Screening Visit; 26. Any subjects with planned elective surgery; 27. Any other arthritic or medical condition that in the opinion of the investigator could interfere with study evaluations; 28. Participation in any clinical research study evaluating another investigational drug or therapy within 30 days or at least 5 half-lives, whichever is longer, of the investigational drug, prior to the Screening Visit.

Study Drug Dosage and Administration. Subjects returned to the clinic for the Baseline visit on Day-1. Once eligibility was confirmed via pre dose procedures, the subject was randomly allocated to receive either mAb1 or placebo. Dose assignments were determined by the allocation schedule. Dosing took place starting at approximately 08:00 on Day 1. Subjects were required to be fasting (no food or water) beginning at midnight on Day-1. Study doses of 50, 100, and 200 mg were administered via subcutaneous injection. Each dose was administered in a single injection. All study drug injections were administered in the abdomen.

Dose Preparation. Study drug was supplied as lyophilized powder in sterile, single-use vials. Each vial contained 250 mg of mAb1 and provided a stock solution of 100 mg/ml after reconstitution. Placebo was supplied in matched vials. mAb1 was reconstituted in Sterile Water For Injection (WFI), and contained a withdrawable volume of up to 2.0 ml. Dosing volume was 0.5 ml for the 50 mg dose, 1.0 ml for the 100 mg dose, and 2.0 ml for the 200 mg dose.

Study Procedures and Visits. Physical Examination. A physical examination was conducted at the Screening visit, Day-1 (Visit 2), Day 15 (Visit 7), and Day 113 (Visit 14, EOS). Vital Signs Vital signs including temperature, sitting blood pressure, pulse and respiration were collected at every study visit. On Day 1 (Visit 3), vital signs were done prior to each pharmacokinetic blood draw at hour 0 (pre-dose) and at hour 8 post dose. Pharmacokinetic and Antibody Sample Collection Serum samples were collected for pharmacokinetic (PK) analysis at every study visit beginning on Day 1 (Visit 3). On Day 1 (Visit 3), samples were collected at hour 0 (pre-dose) and at hour 8±3 minutes (post-dose). PK samples were subsequently collected at the same time each day on Study Days 3, 4, 8, 11, 15, 22, 29, 43, 57, 85 and 113 (±2 hours). Serum samples were collected for analysis of antibodies to mAb1 .

PPD Skin Test. Tuberculin purified protein derivative (PPD) 5TU skin test were placed intradermally at the time of the Screening visit and read 48 to 72 hours after inoculation. All subjects, with the exception of subjects who tested PPD positive and were successfully treated with anti-tuberculosis therapy, but including those with a prior history of Bacillus Calmette Guerin (BCG) administration received a PPD 5TU skin test. Subjects' successful treatment for a prior tuberculosis infection was documented in the source document, if applicable. Those subjects with a positive PPD 5TU skin test, mm induration at 48 to 72 hours were excluded from the study.

Chest X-Ray. A radiologist's interpretation (signed and dated) of the standard posterior-anterior and lateral chest X-rays noted the absence of calcified granulomas and/or pleural scarring consistent with TB. This information was documented in the subject's medical chart and on the appropriate case report form at the Screening visit. A normal chest X-ray report was deemed acceptable if it had been done within the three months prior to the Screening visit.

Electrocardiogram. A standard 12-lead electrocardiogram (ECG) was performed at the Screening visit, Day 3 (Visit 4), Day 8 (Visit 6), Day 15 (Visit 8) and Day 29 (Visit 10). Heart rate was recorded from the ventricular rate and the PR, QRS, QT and QTc (QTc=QT/[60/heart rate]1/2) intervals were recorded.

Subject's Assessment of Pain. An 11-point scale (0=no pain to 10=severe pain) was used to measure the subject's current level of pain. The subject was instructed to circle a box on the continuum indicating the appropriate response.

Subject's Global Assessment of Disease Activity. An 11-point scale (0=no symptoms to 10=severe symptoms) was used to measure the subject's overall assessment of his/her current disease activity. The subject was instructed to circle a box on the continuum indicating the appropriate response.

Additional Sample Collection. Blood and urine were collected as indicated for routine laboratory measurements. Subjects fasted beginning at midnight on the Day-1 (Visit 2, Baseline) and Day 43 (Visit 10, EOS) study visits. Plasma and/or serum samples were collected as indicated and used for future analysis of serum proteins (i.e. proteomic analysis) as related to underlying disease in response to IL-6.

Schedule of Study Visits. Visit 1; Screening Visit (Day-14 to Day-3): Informed Consent, Inclusion/Exclusion Criteria, Medical History, Physical Examination, Height and Weight, Vital Signs, Chest x-ray, PPD Skin Test 5TU (read at 48 to 72 hours), Electrocardiogram, Serum HCG pregnancy test (for women of childbearing potential), Hepatitis C Virus (HCV) Ab, Hepatitis B Surface Antigen (HBsAg), HgbA1c, Hematology panel, Chemistry panel, Urinalysis, High sensitivity C-Reactive Protein (hs-CRP) and Serum Amyloid A (SAA), Erythrocyte Sedimentation Rate (ESR), IL-6 and fibrinogen, Concomitant medications, Adverse Events. Visit 2; Day-1: Vital Signs, Weight, Urine pregnancy test (for women of childbearing potential), Hematology panel, Chemistry panel, Urinalysis, Concomitant medications, Adverse events, Randomization. Visit 3, Dosing, Day 1, Baseline: Vital signs, Urine pregnancy test (for women of childbearing potential), Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Rheumatoid Factor/ANA/anti-dsDNA, Serum immunoglobulins, Serum ferritin, Iron, Total Iron Binding Capacity (TIBC), RNA, Proteomics sample, Pharmacokinetic blood draw (0 hours pre-dose and 8 hours post dose), Anti-mAb1 antibody, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Concomitant medications, Adverse events. Visit 4, Day 3: Vital signs, Electrocardiogram, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, RNA, Proteomics sample, Pharmacokinetic blood draw, Anti-mAb1 antibody, Concomitant medications, Adverse events. Visit 5, Day 4: Vital signs, Hematology panel, Chemistry panel, Urinalysis, Pharmacokinetic blood draw, RNA, Proteomic sample, Concomitant medications, Adverse events. Visit 6, Day 8: Vital signs, Electrocardiogram, Urine pregnancy test, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Pharmacokinetic blood draw, RNA, Proteomic sample, Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications, Adverse events. Visit 7, Day 11: Vital signs, Hematology panel, Chemistry panel, Pharmacokinetic blood draw, Concomitant medications, Adverse events. Visit 8, Day 15±1 day: Physical examination, Vital signs, Electrocardiogram, Urine pregnancy test, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Pharmacokinetic blood draw, RNA, Proteomics sample, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Concomitant medications, Adverse events. Visit 9, Day 22±1 day: Vital signs, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Pharmacokinetic blood draw, Concomitant medications, Adverse events. Visit 10, Day 29±1 day: Vital signs, Electrocardiogram, Urine pregnancy test, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Serum ferritin, Iron, TIBC, Pharmacokinetic blood draw, RNA, Proteomics sample, Anti-mAb1 antibody, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Concomitant medications, Adverse events. Visit 11, Day 43±1 day: Vital signs, Hematology panel, Chemistry panel, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Pharmacokinetic blood draw, Concomitant medications, Adverse events. Visit 12, Day 57±1 day: Vital signs, Urine pregnancy test, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Rheumatoid Factor/ANA/anti-dsDNA, Serum immunoglobulins, Serum ferritin, Iron, TIBC, Pharmacokinetic blood draw, RNA, Proteomics sample, Anti-mAb1 antibody, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Concomitant medications, Adverse events.

Visit 13, Day 85±1 day: Vital signs, Hematology panel, Chemistry panel, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Pharmacokinetic blood draw, Concomitant medications, Adverse events. Visit 14, End of Study, Day 113±3 day: Physical examination, Vital signs, Weight, Height, Urine pregnancy test, Electrocardiogram, Serum pregnancy test, Hematology panel, Chemistry panel, Urinalysis, hs-CRP and SAA, ESR, IL-6 and fibrinogen, Rheumatoid Factor/ANA/anti-dsDNA, Serum immunoglobulins, Serum ferritin, Iron, TIBC, Pharmacokinetic blood draw, RNA, Proteomics sample, Anti-mAb1 antibody, Subject's Assessment of Pain, Subject's Global Assessment of Disease Activity, Concomitant medications, Adverse events.

Results: Baseline levels of RA-associated biomarkers (hsCRP, SAA, ESR, IL-6, Hb, and hepcidin) measured prior to administration of mAb1 or placebo are shown in Table 6 (n=15).

TABLE 6 hsCRP 5.6 mg/L SAA 4252 ng/mL ESR 19 mm/hr IL-6 4.1 pg/mL Hb 12.3 g/dL Mean hepcidin 82.5 ng/mL Median hepcidin 60.8 ng/mL

Median hepcidin levels (in ng/mL) over the course of the study are shown in Table 7.

TABLE 7 mAb1 dose (mg) Study Day 0 50 100 200 D1  57.6 38.5 66.3 87.8 D4  8.8 39.6 22.8 49.3 D8  13.9 49.5 25.9 38.1 D29 0 24.0 55.5 66.5

The hepcidin levels for individual study participants is set forth in Table 8.

TABLE 8 Serum Hepcidin (ng/mL) Subject Treatment Day 1 Day 4 Day 8 Day 29 1002  50 mg mAb1 30.39 38.57 43.99 0 1004  50 mg mAb1 229.22 40.55 140.58 200.43 1005  50 mg mAb1 0 0 0 8.99 1003  50 mg mAb1 46.69 67.83 55.09 39.00 1016 100 mg mAb1 8.01 0 25.35 0 1019 100 mg mAb1 71.82 45.55 26.35 39.70 1020 100 mg mAb1 60.80 0 17.50 147.81 1017 100 mg mAb1 88.88 49.77 156.34 71.36 1033 200 mg mAb1 0 9.00 0 0 1034 200 mg mAb1 37.10 54.81 6.48 27.14 1031 200 mg mAb1 138.56 43.80 69.65 105.91 1032 200 mg mAb1 226.18 101.92 150.01 157.49 1001 placebo 0 0 0 0 1018 placebo 115.12 229.96 169.06 96.82 1035 placebo 184.70 17.64 27.69 0

Safety was assessed by measuring neutrophils and alanine aminotransferase (ALT), as shown in Tables 9 and 10, respectively (ULN=upper limit of normal).

TABLE 9 Treatment Group 50 mg 100 mg 200 mg Combined mAb1 + mAb1 + mAb1 + mAb1 + Neutrophil MTX MTX MTX MTX MTX Range (n = 3) (n = 4) (n = 4) (n = 4) (n = 12) <1.5 × 10³/μL 0 1 (25%) 0 2 (50%) 3 (25%) <1.0 × 10³/μL 0 0 0 0 0 <0.5 × 10³/μL 0 0 0 0 0

TABLE 10 Treatment Group 50 mg 100 mg 200 mg Combined mAb1 + mAb1 + mAb1 + mAb1 + MTX MTX MTX MTX MTX ALT Range (n = 3) (n = 4) (n = 4) (n = 4) (n = 12) >1 × ULN 0 0 1 (25%) 3 (75%) 4 (33.3%) >2 × ULN 0 0 0 2 (50%) 2 (16.7%) >3 × ULN 0 0 0 0 0 >5 × ULN 0 0 0 0 0 >8 × ULN 0 0 0 0 0

Example 11 Study in RA Subjects Receiving Concomitant Methotrexate

A second study was conducted to assess the safety and tolerability of multiple doses of subcutaneously administered mAb1 in subjects with rheumatoid arthritis who were receiving concomitant treatment with methotrexate. The study was conducted in three parts and included a total of 6 dose cohorts. Parts B and C began after the safety of Part A was assessed.

Part A: Dose cohort 1: 10 subjects were randomized (4:1) to receive either: 50 mg mAb1 SC every week (8 subjects) or placebo every week (2 subjects). Dose cohort 2: 10 subjects were randomized (4:1) to receive either: 100 mg mAb1 SC alternating with placebo every week (8 subjects), or placebo every week (2 subjects). Upon confirmation of the safety of Part A, enrollment in Part B was opened: Part B: Dose cohort 3: 10 subjects were randomized (4:1) to receive either: 100 mg mAb1 SC every week (8 subjects) or placebo every week (2 subjects). Dose cohort 4: 10 subjects were randomized (4:1) to receive either: 200 mg mAb1 SC alternating with placebo every week (8 subjects), or placebo every week (2 subjects). Dose cohort 5: 10 subjects were randomized (4:1) to receive either: 150 mg mAb1 SC every week (8 subjects) or placebo every week (2 subjects). Part C: Dose cohort 6: 10 subjects were randomized (4:1) to receive either: 150 mg mAb1 SC every other week (8 subjects) or placebo every other week (2 subjects).

All subjects completed 5 weeks of treatment (dosing on Day 1, Weeks 1, 2, 3 and 4), followed by 5 weeks of safety follow-up, for a total duration of 10 weeks. Subjects completed 12 study visits (Screening, Day 1 (first dose, Baseline Visit), Day 8 (Week 1), Day 15 (Week 2), Day 22 (Week 3), Day 29 (Week 4), Day 36 (Week 5), Day 43 (Week 6), Day 50 (Week 7), Day 57 (Week 8), Day 64 (Week 9) and Day 71 (Week 10).

Inclusion Criteria: 1. Male or female ≧18 years of age; 2. Subjects weigh >50 kg and <100 kg; 3. Diagnosis of Rheumatoid Arthritis (RA) as defined by the 1987 revised American College of Rheumatology (ACR) criteria with disease duration of no less than 6 months and ACR class I-III; 4. Subjects must have received a minimum of 12 weeks treatment with methotrexate (MTX) prior to the Screening visit. Subjects must be on a stable dose of MTX (7.5 to 25 mg/week) for a minimum of 6 weeks prior to the Screening Visit; 5. All subjects took folic acid 1 mg daily or 5 mg weekly with the MTX dose, to minimize toxicity, according to local guidelines; 6. For men and women of childbearing potential, willingness to utilize adequate contraception and not become pregnant (or have their partner[s] become pregnant) during the full course of the study. Adequate contraceptive measures include oral contraceptives (stable use for 2 or more cycles prior to the Screening visit); IUD; DEPO-PROVERA®; NORPLANT® System implants; bilateral tubal ligation; vasectomy; condom or diaphragm plus either contraceptive sponge, foam or jelly.

Exclusion Criteria: 1. A history of Listeriosis or active tuberculosis (TB); 2. Persistent chronic or active recurring infection requiring treatment with antibiotics, antivirals, or antifungals within 4 weeks prior to the Screening Visit, or any active infection at the time of screening or randomization; 3. History of prior articular or prosthetic joint infection; 4. History of a hypersensitivity reaction, other than localized injection site reaction (ISR), to any biological molecule; 5. History of a hypersensitivity reaction to doxycycline, tetracycline or related compounds; 6. Significant concomitant illness such as, but not limited to cardiac, renal, neurological, endocrinological, metabolic or lymphatic disease that would adversely affect the subject's participation in this study; 7. Uncontrolled diabetes, defined as Hemoglobin A1c (HbA1c) ≧9.0% at the Screening Visit; 8. Presence of any of the following laboratory abnormalities at the Screening Visit: WBC <4,000/·L; platelet count <150,000·L; neutrophils <2000/·L, AST/ALT >1.5×ULN; 9. Serum creatinine×ULN at the Screening Visit; 10. Subjects with a positive intradermal skin tuberculin test (PPD 5TU)≧5 mm induration read at 48 to 72 hours after placement; 11. Chest radiograph (at the Screening visit) consistent with prior tuberculosis infection including, but not limited to, apical scarring, apical fibrosis, or multiple calcified granulomata. This does not include non-caseating granulomata; 12. Use of oral prednisone or equivalent >10 mg per day within 4 weeks prior to the Screening Visit; 13. Use of parenteral or intra-articular glucocorticoids within 4 weeks prior to the Screening Visit; 14. Treatment with anakinra within two weeks prior to the Screening Visit; 15. Treatment with etanercept, cyclosporine, mycophenolate, tacrolimus, gold, penicillamine, sulfasalazine, or hydroxychloroquine within 4 weeks prior to the Screening Visit; 16. Treatment with adalimumab within 6 weeks prior to the Screening Visit; 17. Treatment with abatacept, azathioprine, cyclophosphamide or infliximab within 12 weeks prior to the Screening Visit; 18. Treatment with leflunomide or rituximab within 6 months prior to the Screening Visit; 19. Use of tocilizumab or any other anti-IL-6 medication prior to the Screening Visit; 20. Prior exposure to mAb1; 21. Received administration of any live (attenuated) vaccine within 3 months prior to the Screening Visit; 22. Known history of Human Immunodeficiency Virus (HIV) antibody; and/or positive Hepatitis B surface antigen (HBsAg), and/or positive Hepatitis C antibody (HCV) at the Screening Visit; 23. History of malignancy other than adequately treated carcinoma in-situ of the cervix, or adequately treated, non-metastatic squamous or basal cell carcinoma of the skin within five years prior to Screening Visit; 24. History of demyelinating disease or multiple sclerosis; 25. History of myeloproliferative disorder; 26. History of alcohol or drug abuse within the 5 years prior to the Screening Visit; 27. Any subject who has had surgery within 4 weeks prior to the Screening Visit; 28. Any subjects with planned elective surgery; 29. Any other arthritic or medical condition that in the opinion of the investigator could interfere with study evaluations; 30. Participation in any clinical research study evaluating another investigational drug or therapy within 30 days or at least 5 half-lives, whichever is longer, of the investigational drug, prior to the Screening Visit.

Study drug was supplied as a lyophilized powder in sterile, single-use vials. Each vial contained 269 mg of mAb1 and provided a stock solution of 100 mg/mL after reconstitution. Placebo was supplied in matched vials. mAb1 was reconstituted in Sterile Water for Injection (WFI), and contained a withdrawable volume of up to 2 mL.

Study Drug Dosage. Subjects had a Screening Visit on Day-14 to Day-3. Once eligibility was confirmed, the subjects were randomly allocated to receive either mAb1 or placebo. Dose assignment into each group was determined by an IVRS. In Part A, subjects were randomized into two dose cohorts. Subjects in dose cohort 1 received either 50 mg mAb1 SC every week or matching placebo every week and subjects in cohort 2 received either 100 mg mAb1 SC alternating with placebo every week or matching placebo every week. Subjects in dose cohort 2 received a dose of 100 mg SC mAb1 on Day 1 (Visit 2), Day 15 (Visit 4) and Day 29 (Visit 6) and a dose of placebo on Day 8 (Visit 3) and Day 22 (Visit 5). Escalation to Part B took place after all 20 subjects in Part A completed the Day 36 (Week 5) visit and the laboratory and safety data were reviewed, and the safety of the 200 mg single dose was confirmed. Subjects in Part B were randomized into three dose cohorts. Subjects in dose cohort 3 received either 100 mg mAb1 SC every week or matching placebo every week; subjects in cohort 4 received either 200 mg mAb1 SC alternating with placebo every week or matching placebo every week and subjects in dose cohort 5 received either 150 mg mAb1 SC every week or matching placebo every week. Subjects in dose cohort 4 received a dose of 200 mg SC mAb1 on Day 1 (Visit 2), Day 15 (Visit 4) and Day 29 (Visit 6) and a dose of placebo on Day 8 (Visit 3) and Day 22 (Visit 5).

Schedule of Study Visits. Screening; Visit 1; Day-14 to Day-3: Informed Consent; Inclusion/Exclusion Criteria; Medical History; Physical Examination; Height and Weight; Vital Signs; Chest x-ray (PA and Lateral); PPD skin test 5 TU (to be read at 48 to 72 hours); hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Electrocardiogram; Serum βHCG pregnancy test (for women of childbearing potential); HCV Ab and HBsAg; HbA1c; Hematology panel; Chemistry panel; Urinalysis; Concomitant medications; Adverse Events. Visit 2; Baseline Visit; Day 1: Vital Signs, Weight; Urine pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Serum immunoglobulins; Rheumatoid Factor/ANA/anti-dsDNA; RNA; Proteomic sample; Plasma for MTX analysis; Pharmacokinetic blood draw; Anti-mAb1 antibody; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events; Randomization; Study drug administration. Visit 3; Day 8 (Week 1) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; RNA; Proteomic sample; Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events; Study drug administration. Visit 4; Day 15 (Week 2) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events; Study drug administration. Visit 5: Day 22 (Week 3) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events; Study drug administration. Visit 6: Day 29 (Week 4) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events; Study drug administration. Visit 7: Day 36 (Week 5) (±1 day): Vital signs; Electrocardiogram; Urine pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Plasma for MTX analysis; Pharmacokinetic blood draw; Anti-mAb1 antibody; Proteomic sample; RNA; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events. Visit 8; Day 43 (Week 6) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); Plasma for MIX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 9; Day 50 (Week 7) (±1 day): Vital signs, Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 10: Day 57 (Week 8) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; RNA; Proteomic sample; Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 11: Day 64 (Week 9) (±1 day): Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); Plasma for MTX analysis; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 12: Day 71 (Week 10) (±1 day); End of Study: Physical Examination; Vital Signs; Weight; Height; Electrocardiogram; Serum pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP; Complement (C3, C4 and CHSO); SAA, fibrinogen, IL-6; ESR; Serum immunoglobulins; Rheumatoid Factor/ANA/anti-dsDNA; RNA; Proteomic sample; Plasma for MTX analysis; Pharmacokinetic blood draw; Anti-mAb1 antibody; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events.

Results: Baseline levels of RA-associated biomarkers (hsCRP, SAA, ESR, IL-6, Hb, and hepcidin) measured prior to administration of mAb1 or placebo are shown in Table 11 (n=47).

TABLE 11 hsCRP 4.6 SAA 5800 ESR 25 IL-6 4.5 Hemoglobin 13.3 Mean hepcidin 102.6 Median hepcidin 76.9

Safety was assessed by measuring neutrophils and alanine aminotransferase (ALT), as shown in Tables 12 and 13, respectively (qw=weekly dosing; q2w=biweekly dosing of mAb1 alternating with placebo).

TABLE 12 Treatment Group I Neutrophil 50 mg mAb1 qw + 100 mg mAb1 100 mg mAb1 Range MTX (n = 13) MTX (n = 8) q2w + MTX (n = 8) qw + MTX (n = 8) <1.5 × 10³/μL 1 (8%) 0 0 2 (25%) <1.0 × 10³/μL 0 0 0 1 (13%) <0.5 × 10³/μL 0 0 0 0 Treatment Group II Neutrophil 200 mg mAb1 150 mg mAb1 150 mg mAb1 Combined mAb1 + Range q2w + MTX (n = 7) qw + MTX (n = 8) q2w + MTX (n = 8) MIX (n = 47) <1.5 × 10³/μL 3 (43%) 3 (38%) 0 8 (17%) <1.0 × 10³/μL 1 (14%) 1 (13%) 0 3 (6%) <0.5 × 10³/μL 0 0 0 0

TABLE 13 Treatment Group I 50 mg mAb1 qw + 100 mg mAb1 100 mg mAb1 ALT Range MTX (n = 13) MTX (n = 8) q2w + MTX (n = 8) qw + MTX (n = 8)   >1 × ULN 3 (23 %) 2 (25%) 4 (50%) 6 (75%) >1.5 × ULN 0 1 (13%) 1 (13%) 4 (50%)   >2 × ULN 0 0 0 2 (25%)   >3 × ULN 0 0 0 0 Treatment Group II 200 mg mAb1 150 mg mAb1 150 mg mAb1 Combined mAb1 + ALT Range q2w + MTX (n = 7) qw + MTX (n = 8) q2w + MTX (n = 8) MTX (n = 47)   >1 × ULN 4 (57%) 4 (50%) 1 (13%) 21 (45%) >1.5 × ULN 2 (29%) 2 (25%) 0 10 (21%)   >2 × ULN 1 (14%) 1 (13%) 0 4 (9%)   >3 × ULN 0 0 0 0

Example 12 Subcutaneously Administered mAb1 in Subjects with Rheumatoid Arthritis

A third study was conducted to assess the bioeffect of a single dose of mAb1 compared with placebo in subjects with active rheumatoid arthritis who were receiving concomitant treatment with methotrexate.

Study Design. The study was designed as a single-dose, double-blind, placebo-controlled, parallel group safety, tolerability and pharmacodynamic study of subcutaneously (SC) administered mAb1 in rheumatoid arthritis patients who are receiving concomitant methotrexate. Four (4) parallel groups of 8 subjects each with active rheumatoid arthritis were dosed SC with 50, 100 or 200 mg mAb1 or placebo (1:1:1:1). Each subject received a single dose of mAb1 or placebo, and was followed for 6 weeks. Subjects (32) completed 10 study visits: (Screening, Day 1, Day 4, Day 8, Day 12, Day 15, Day 22, Day 29, Day 36 and Day 43).

Inclusion Criteria: 1. Male or female ≧18 years of age; 2. Subjects must weigh >50 kg and <100 kg; 3. Diagnosis of Rheumatoid Arthritis (RA) as defined by the 1987 revised American College of Rheumatology (ACR) criteria with disease duration of no less than 6 months and ACR class I-III; 4. Subjects must receive a minimum of 12 weeks treatment with methotrexate (MTX) prior to the Screening visit. Subjects must be on a stable dose of MTX (7.5 to 25 mg/week) for a minimum of 8 weeks prior to the Screening Visit; 5. All subjects will take folic acid at 5 mg weekly or greater with the MTX dose, to minimize toxicity; 6. hs-CRP ≧10 mg/L; 7. For men and women of childbearing potential, willingness to utilize adequate contraception and not become pregnant (or have their partner[s] become pregnant) during the full course of the study. Adequate contraceptive measures include oral contraceptives (stable use for 2 or more cycles prior to screening) and other prescription pharmaceutical contraceptives; IUD; bilateral tubal ligation; vasectomy; condom or diaphragm plus either contraceptive sponge, foam or jelly.

Exclusion Criteria: 1. A history of Listeriosis or active tuberculosis (TB); 2. Persistent chronic or active recurring infection requiring treatment with antibiotics, antivirals, or antifungals within 4 weeks prior to the Screening Visit; 3. History of prior articular or prosthetic joint infection; 4. History of a hypersensitivity reaction, other than localized injection site reaction (ISR), to any biological molecule; 5. History of a hypersensitivity reaction to doxycycline, tetracycline or related compounds; 6. Significant concomitant illness such as, but not limited to cardiac, renal, neurological, endocrinological, metabolic or lymphatic disease that would adversely affect the subject's participation in this study; 7. Uncontrolled diabetes, defined as Hemoglobin A1c (HbA1c) ≧9.0% at the Screening Visit; 8. Presence of any of the following laboratory abnormalities at the Screening Visit: WBC <4,000/μ; platelet <150,000/μl; neutrophils <2000/0, AST/ALT >1.5×ULN; 9. Serum creatinine ≧1.5×ULN at the Screening Visit; 10. Subjects with a positive intradermal skin tuberculin test ≧5 mm induration read at 48 to 72 hours after placement; 11. Chest radiograph (at the Screening visit) consistent with prior tuberculosis infection including, but not limited to, apical scarring, apical fibrosis, or multiple calcified granulomata. This does not include non-caseating granulomata; 12. Treatment with oral prednisone or equivalent >10 mg per day within 4 weeks prior to the Screening Visit; 13. Use of parenteral or intra-articular glucocorticoids within 4 weeks prior to the Screening Visit; 14. Treatment with anakinra within two weeks prior to the Screening Visit; 15. Treatment with etanercept, cyclosporine, mycophenolate, taerolimus, gold, penicillamine, sulfasalazine, or hydroxychloroquine within 4 weeks prior to the Screening Visit; 16. Treatment with adalimumab within 6 weeks prior to the Screening Visit; 17. Treatment with abatacept, azathioprine, cyclophosphamide or infliximab within 12 weeks prior to the Screening Visit; 18. Treatment with leflunomide or rituximab within 6 months prior to the Screening Visit; 19. Treatment with tocilizumab or any other anti-IL-6 medication prior to Screening Visit; 20. Start treatment or change dose of current treatment with NSAIDs/COX2 inhibitors for 2 weeks prior to Screening; 21. Received administration of any live (attenuated) vaccine within 3 months prior to the Screening Visit; 22. Known history of Human Immunodeficiency Virus (HIV) antibody; and/or positive Hepatitis B surface antigen (HBsAg), and/or positive Hepatitis C antibody (HCV) at the Screening Visit; 23. History of malignancy other than carcinoma in-situ of the cervix, or adequately treated, non-metastatic squamous or basal cell carcinoma of the skin within five years prior the Screening Visit; 24. History of alcohol or drug abuse within the 5 years prior to the Screening Visit; 25. Any subject who has had surgery within 4 weeks prior to the Screening Visit; 26. Any subjects with planned elective surgery; 27. Participation in any clinical research study evaluating another investigational drug or therapy within 30 days or at least 5 half-lives, whichever is longer, of the investigational drug, prior to the Screening Visit; 28. Previous exposure to mAb1.

Study Drug Dosage. Subjects had a Screening Visit on Day-14 to Day-3. Once eligibility was confirmed, the subjects were randomly allocated to receive either mAb1 or placebo. Subjects were enrolled in 4 parallel groups of 8 subjects each and were dosed with 50, 100 or 200 mg SC mAb1 or placebo (1:1:1:1). Each subject received a single SC dose of mAb1 or placebo on Day 1, and was followed for 6 weeks.

Dose Preparation. Study drug was supplied as lyophilized powder in sterile, single-use vials. Each vial contained 269 mg of mAb1 and provided a stock solution of 100 mg/ml after reconstitution. The maximum dose to be administered per vial was 200 mg. Placebo was supplied in matched vials. mAb1 was reconstituted in Sterile Water For Injection (WFI), and contained a withdrawable volume of up to 2 ml. The 50 mg dose was administered at 0.5 ml, 100 mg at 1 ml, 200 mg at 2 ml and the placebo at 2 ml. All study drug injections were administered in the abdomen.

Screening; Visit 1; Day-14 to Day-3 (±2 days): Informed Consent; Inclusion/Exclusion Criteria; Medical History; Physical Examination; Height and Weight; Vital Signs; Chest x-ray (PA and Lateral); Tuberculin Skin Test (read at 48 to 72 hours); hs-CRP and SAA; ESR; Electrocardiogram; Serum βHCG pregnancy test (for women of childbearing potential); HCV Ab and HBsAg; Hematology panel; Chemistry panel; Urinalysis; Concomitant medications; Adverse Events. Visit 2; Baseline Visit; Day 1: Vital Signs; Weight; Urine pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; Serum immunoglobulins; Rheumatoid Factor/ANA/anti-dsDNA; RNA; Proteomic sample; Pharmacokinetic blood draw; Anti-mAb1 antibody; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events; Randomization; Study drug administration. Visit 3; Day 4: Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; RNA; Proteomic sample; Pharmacokinetic blood draw; Anti-mAb1 antibody; Concomitant medications; Adverse events. Visit 4; Day 8: Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; RNA; Proteomic sample; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 5: Day 12: Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; RNA; Proteomic sample; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 6; Day 15: Vital Signs; Urine pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 7: Day 22: Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; RNA; Proteomic sample; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 8; Day 29: Vital Signs; Urine pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; Electrocardiogram; hs-CRP and SAA; ESR; IL-6; Serum immunoglobulins; Rheumatoid Factor/ANA/anti-dsDNA; RNA; Anti-mAb1 antibody; Proteomic sample; Pharmacokinetic blood draw; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events. Visit 9; Day 36: Vital signs; Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; RNA; Proteomic sample; Pharmacokinetic blood draw; Concomitant medications; Adverse events. Visit 10; Day 43; End of Study: Physical examination; Vital signs; Height and weight; Electrocardiogram; Serum βHCG pregnancy test (for women of childbearing potential); Hematology panel; Chemistry panel; Urinalysis; hs-CRP and SAA; ESR; IL-6; Serum immunoglobulins; Rheumatoid Factor/ANA/anti-dsDNA; RNA; Proteomic sample; Pharmacokinetic blood draw; Anti-mAb1 antibody; Subject's Assessment of Pain; Subject's Global Assessment of Disease Activity; Concomitant medications; Adverse events.

Results: Baseline levels of RA-associated biomarkers (hsCRP, SAA, ESR, IL-6, Hb, and hepcidin) measured prior to administration of mAb1 or placebo are shown in Table 14 (n=24).

TABLE 14 hsCRP 21.2 SAA 45713 ESR 48 IL-6 28.8 Hemoglobin 12.3 Mean hepcidin 86.5 Median hepcidin 70.2

The median percent hepcidin change at day 8 is summarized in Table 15.

TABLE 15 mAb1 dose (mg) Study Day 0 50 100 200 D8 −2.4 0.0 −21.0 −66.2

The hepcidin levels for individual study participants at Day 1 and Day 8 are set forth in Table 16. UD: Undetected.

TABLE 16 Serum Hepcidin Subject mAb1 (ng/mL) No. Treatment Day 1 Day 8 1-0008  50 mg 166.2 136.3 3-0003  50 mg 22.7 35.3 4-0003  50 mg 71.9 27.6 5-0004  50 mg UD UD 5-0006  50 mg 25.0 27.4 6-0001  50 mg 109.2 6.8 9-0005  50 mg 60.8 — 11-001   50 mg 35.4 37.8 1-0006 100 mg 298.9 203.6 2-0002 100 mg 97.4 113.7 2-0003 100 mg 70.1 9.0 2-0007 100 mg 189.1 12.4 3-0002 100 mg UD UD 8-0007 100 mg 38.3 34.4 11-002  100 mg 60.3 20.3 11-008  100 mg 15.2 18.5 2-0001 200 mg 92.8 11.6 5-0005 200 mg 47.3 20.3 5-0007 200 mg 12.2 5.2 6-0006 200 mg 12.9 UD 6-0007 200 mg UD UD 10-001  200 mg 171.8 94.2 11-005  200 mg 148.9 37.7 11-007  200 mg 145.1 UD 1-0004 Placebo 254.7 242.6 2-0006 Placebo 215.8 73.5 5-0003 Placebo 49.0 66.0 6-0002 Placebo 75.0 52.1 6-0003 Placebo UD UD 8-0006 Placebo 76.8 57.1 9-0002 Placebo 133.2 267.6 9-0009 Placebo 47.5 72.1

The percent change in high-sensitivity C-reactive protein (hsCRP) and circulating IL-6 levels are summarized in Tables 17 and 18, respectively.

TABLE 17 Placebo 50 mg mAb1 100 mg mAb1 200 mg mAb1 Combined Baseline value N 8 8 8 8 24 Mean (SD) 29.58 (24.55) 21.97 (16.82) 23.43 (17.53) 34.07 (27.46) 26.49 (20.96) Median 21.150 16.250 24.400 29.800 24.200 Min:Max 5.43:78.70 5.29:48.20 1.22:44.40 8.12:96.10 1.22:96.10 % Change from Baseline at Day 4 N 6 6 4 4 14 Mean (SD) −16.58 (23.84) −7.98 (71.17) −39.39 (18.82) −66.54 (15.29) −33.68 (52.26) Median −16.27 −21.42 −38.19 −65.24 −46.50 Min:Max −55.4:11.6 −75.1:124.6 −63.3:−17.9 −84.5:−51.2 −84.5:124.6 P-value — 0.8182 0.1714 0.0190 0.1093 compared with placebo % Change from Baseline at Day 8 N 8 8 8 8 24 Mean (SD) 9.09 (52.09) −16.42 (40.23) −69.18 (28.62) −89.21 (6.60) −58.27 (41.70) Median −2.99 −17.27 −72.42 −91.66 −75.97 Min:Max −57.2:95.5 −77.7:36.5 −96.6:−8.7 −94.4:−74.3 −96.6:36.5 P-value — 0.4418 0.0011 0.0002 0.0017 compared with placebo

TABLE 18 Placebo 50 mg mAb1 100 mg mAb1 200 mg mAb1 Combined Baseline value N 8 8 8 8 24 Mean (SD) 33.94 (31.25) 40.39 (26.55) 25.59 (18.58) 59.53 (68.35) 41.83 (44.08) Median 21.875 47.160 26.090 24.520 33.400 Min:Max 6.22:90.63 5.30:78.42 2.81:45.11 3.69:190.2 2.81:190.02 % Change from Baseline at Day 4 N 6 7 4 4 15 Mean (SD) 1.39 (17.49) 514.04 318.17 521.69 463.85 (603.32) (191.69) (471.82) (468.89) Median 3.50 244.85 259.08 351.40 268.79 Min:Max −25.9:21.2 −45.8:1537.5 158.2:596.3 173.2:1210.7 −45.8:1537.5 P-value — 0.0513 0.0095 0.0095 0.0016 compared with placebo % Change from Baseline at Day 8 N 8 8 8 8 24 Mean (SD) −8.55 (27.60) −13.21 (59.00) 748.40 966.87 567.69 (685.54) (984.69) (789.60) Median −1.53 −9.10 596.91 647.02 292.18 Min:Max −55.3:24.6 −95.4:94.0 31.7:1857.0 −71.4:2836.8 −95.4:2836.8 P-value — 0.7209 0.0002 0.0104 0.0228 compared with placebo

Median percent changes from baseline for hs-CRP (Table 19), IL-6 (Table 20), hemoglobin (Table 21), serum amyloid A (Table 22), and erythrocyte sedimentation rate (Table 23) are shown below.

TABLE 19 Placebo 50 mg 100 mg 200 mg Day 1 — — — — Day 4 −16.3 −21.4 −38.2 −65.2 Day 8 −3.0 −17.3 −72.4 −91.7 Day 12 −7.7 −9.6 −6.8 −89.0 Day 15 16.0 −4.7 −19.8 −82.4 Day 22 −3.7 39.0 −10.8 −32.7 Day 29 1.4 −5.2 −38.8 −45.7 Day 36 17.0 −12.3 −28.9 −49.2 Day 43 −19.4 −28.8 14.4 −13.7

TABLE 20 Placebo 50 mg 100 mg 200 mg Day 1 — — — — Day 4 3.5 244.9 259.1 351.4 Day 8 −1.5 −9.1 596.1 647.0 Day 12 −43.7 −17.6 69.1 455.6 Day 15 8.7 −17.6 12.9 36.6 Day 22 −22.6 10.6 −13.8 −12.33 Day 29 16.8 −26.0 10.3 −28.3 Day 36 −3.7 −18.1 −8.5 −5.9 Day 43 −19.3 −11.6 −8.5 −24.0

TABLE 21 Placebo 50 mg 100 mg 200 mg Day −7 125.5 121 128 127.5 Day 1 121.5 125 123.5 121 Day 4 124 112 127 127 Day 8 124 116 126 125.5 Day 12 123 120 121.5 122.5 Day 15 123.5 117.5 118 123.5 Day 22 121 120 123 122 Day 29 117 115.5 122 124.5 Day 36 118 118 116.5 118 Day 43 121 112.5 120 121

TABLE 22 Placebo 50 mg 100 mg 200 mg Day 1 — — — — Day 4 −11.0 −29.1 −32.4 −61.9 Day 8 52.2 −14.2 −71.9 −92.5 Day 12 28.8 −38.6 35.2 −92.4 Day 15 54.4 −5.6 8.0 −72.7 Day 22 34.6 −9.3 3.3 −40.9 Day 29 41.5 −36.9 23.3 −32.0 Day 36 23.0 −48.2 −5.0 −34.4 Day 43 10.4 −41.4 19.8 −11.2

TABLE 23 Placebo 50 mg 100 mg 200 mg Day 1 — — — — Day 4 −15 −30 −16.7 −6.3 Day 8 −5.6 −31.2 −36.3 −33.8 Day 12 3.0 −26.4 −32.1 −46.8 Day 15 18.0 −10.2 −22.9 −36.3 Day 22 12.5 −19.4 −23.1 −18.1 Day 29 26.7 −19.4 −28.4 −4.4 Day 36 33.3 −20.7 −33.3 −5.3 Day 43 12.5 −5.2 −24.9 −13.5

Safety was assessed by measuring neutrophils (Table 24) and alanine aminotransferase (ALT) (Table 25).

TABLE 24 Treatment Group Combined Neutrophil 50 mg mAb1 100 mg mAb1 200 mg mAb1 mAb1 + MTX Range MTX (n = 8) + MTX (n = 8) + MTX (n = 8) + MTX (n = 8) (n = 24) <1.5 × 10³/μL 0 1 (12.5%) 3 (37.5%) 2 (25%) 6 (25%) <1.0 × 10³/μL 0 0 2 (25%) 0 2 (8.3%) <0.5 × 10³/μL 0 0 0 0 0

TABLE 25 Treatment Group Combined 50 mg mAb1 100 mg mAb1 200 mg mAb1 mAb1 + MTX ALT Range MTX (n = 8) + MTX (n = 8) + MTX (n = 8) + MTX (n = 8) (n = 24) >1 × ULN 3 (37.5%) 2 (25%) 6 (75%) 5 (62.5%) 13 (54.2%) >2 × ULN 1 (12.5%) 0 2 (25%) 2 (25%) 4 (16.7%) >3 × ULN 1 (12.5%) 0 0 2 (25%) 2 (8.3%) >5 × ULN 0 0 0 1 (12.5%) 1 (4.17%) >8 × ULN 0 0 0 0 0

The present invention is not to be limited in scope by the specific embodiments describe herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims. 

What is claimed is:
 1. A method for reducing a symptom of rheumatoid arthritis (RA) in a subject, comprising: administering to the subject a therapeutically effective amount of an antibody or antigen-binding fragment thereof which specifically binds to human interleukin-6-receptor (hIL-6R) with a K_(D) of about 500 pM or less as measured by surface plasmon resonance, wherein the antibody or antigen-binding fragment comprises a complementarity determining region (CDR) sequence combination of SEQ ID NOs:21/23/25/29/31/33.
 2. The method of claim 1, wherein the antibody or antigen-binding fragment comprises a HCVR/LCVR pair of SEQ ID NO: 19/27.
 3. The method of claim 1, wherein the antibody or antigen-binding fragment specifically binds to human interleukin-6 (hIL-6R) with a K_(D) of about 300 pM or less as measured b surface s plasmon resonance.
 4. The method of claim 1, wherein the antibody or antigen-binding fragment specifically binds to human interleukin-6 (hIL-6R) with a K_(D) of about 200 pM or less as measured by surface plasmon resonance.
 5. The method of claim 1, wherein the antibody or antigen-binding fragment specifically binds to human interleukin-6 (hIL-6R) with a K_(D) of about 100 pM or less as measured by surface plasmon resonance.
 6. The method of claim 5, further comprising: a second therapeutic agent selected from the group consisting of: methotrexate; sulfasalazine; hydroxychloroquine; leflunomide; etanercept; infliximab; adalimumab; golimumab; rilonacept; anakinra; abatacept; cetiolizumab; and rituximab.
 7. The method of claim 1, wherein the therapeutically effective amount of the antibody or antigen-binding fragment is about 50 mg to about 200 mg.
 8. A method for reducing a symptom of rheumatoid arthritis in a subject, the method comprising: (a) administering to the subject a first dose of a human antibody or antigen-binding fragment thereof which specifically binds to human interleukin-6 receptor (hIL6-R) with a K_(D) of about 500 pM or less as measured by surface plasmon resonance, and (b) administering to the subject at least one subsequent dose of the human antibody or antigen-binding fragment, wherein the antibody or antigen-binding fragment comprises a complementarity determining region (CDR) sequence combination of SEQ ID NOs:21/23/25/29/31/33.
 9. The method of claim 8, wherein the human antibody or antigen-binding fragment comprises a heavy chain variable region (HCVR) and light chain variable region (LCVR) pair (HCVR/LCVR) of SEQ ID NO: 19/27.
 10. The method of claim 8, wherein the first dose and the subsequent dose are each about 50 mg to about 200 mg of the human antibody or antigen-binding fragment.
 11. The method of claim 8, wherein the first dose and the subsequent dose are administered 1 week to 6 weeks apart.
 12. The method of claim 10, wherein the first dose and the subsequent dose are each 50 mg, 100 mg, 150 mg or 200 mg and administered 1 week apart or 2 weeks apart.
 13. The method of claim 12, further comprising administering to the subject one or more subsequent doses of the human antibody or antigen-binding fragment at 50 mg, 100 mg, 150 mg, or 200 mg, weekly or biweekly.
 14. The method of claim 8, further comprising administering a second therapeutic agent to the subject. 